Grammer

Sentence Construction

Sentence must contain both

• a subject

  • what the sentence is about (usually a noun or pronoun)

• a predicate

  • is the part of a sentence that is not the subject. For example, in “I decided what to do,” “decided what to do” is the predicate.

  • asserts or asks something about the subject, or tells the subject to do something.

  • must contain a verb

Many patients undergo ligament reconstructive surgery every year.

These plants have developed a two part photorespiration system.

Clause contains both

• a subject

• a predicate

There are independent clause (sentence) and dependent clause

• sentence = clause. A sentence is:

  • one independent clause

  • a combination of multiple independent clauses

  • a combination of independent and dependent clauses

• clause ≠ sentence

  • a dependent clause is not a sentence.

Even though Darwin hypothesized the theory of sexual selection (dependent clause), he had no explanation for the initial evolution and maintenance of sexually selected traits (independent clause).

Fragments / Incomplete Sentences

• Looks like a sentence but lacks a subject and predicate

• Do not express a complete thought

Before the absorbance of any solution was read, the spectrophotometer was calibrated with a cuvette containing a blank solution.

This experiment dealt with three mutant types of Drosophila melanogaster: serrated wing mutants, curly wing mutants, and stubble hair mutants.

Run on Sentences / Comma Splices

• Two sentences (or independent clauses) inappropriately joined

• Missing punctuation or coordinating conjunction

  • period, semi colon, colon, comma

• Missing coordinating conjunction

  • and, but, yet, for, or, nor, so

In some cases, the rats were removed from the maze after they ate all the fruit loops. In other cases, they were removed after 10 minutes, no matter what they had eaten.

Subject Verb Agreement

The number of the verb must agree with the number of the subject

• Need to correctly identify the subject (not necessarily the first noun)

  From this work have come improved antibiotic drugs.

  An evaluation of the experimental results, as well as the clinical findings, is described.

• Not all plurals end with an “s” (data, formulae, radii)

  These data are significant

• “Either…or…” & “Neither…nor…": the verb agrees with the nearest subject

  Either the samples or the apparatus was contaminated.

• “Either of” & “Neither of”: the verb is singular

  Neither of the sample is large

• Do not omit helping verbs

  The tissue was minced and the samples were incubated.

Active & passive voice

Active voice = subject performs the action

Cannabis increases appetite.

Passive voice = subject receives the action

Appetite is increased by cannabis.

Active voice is livelier and easier to read

It’s OK to use first person pronouns

Journals want you to write active sentence

Use active voice when suitable, particularly when necessary for correct syntax (e.g., “To address this possibility, we constructed a λZap library…,” not “To address this possibility, a λZap library was constructed…").

— Science Magazine

Caution: the implicit subject does not match the explicit subject of the clause it modifies

• Check all words ending in “ing”

  Using sarkosyl to induce nuclear run-on, the transcriptionally inactive b-globin gene in mature erythrocytes was demonstrated to harbor high levels of Pol II at 5' proximal regulatory regions. 💩

  Using sarkosyl to induce nuclear run-on, we demonstrated high levels of Pol II at 5' proximal regulatory regions in the transcriptionally inactive b-globin gene of mature erythrocytes. 👍

• Check for changes between active and passive voice in the same sentence

  Blood flow was allowed to return to baseline before proceeding with the next occlusion. 💩

  We allowed blood flow to return to baseline before proceeding with the next occlusion. 👍

  Blood flow was allowed to return to baseline before the next occlusion was begun. 👍

Avoid very long subjects and a passive verb at the end of the sentence

• Place subject and verb within the first 9 words of the sentence

• Place any list of items at the end of the sentence

  Cannabidiol and THC, cannabinoid receptor agonists, as well as SR141 and SR144, cannabinoid receptor antagonists, were used. 💩

  Four drugs were used: cannabidiol and THC, cannabinoid receptor agonists; and SR141 and SR144, cannabinoid receptor antagonists. 👍

Sometimes it is better to use the passive voice

• The methods section

• To increase cohesion between sentences

Balance between active and passive voice

Be aware

Choose passive voice for reason, not because you think it sounds scientific

Verb tenses

Most common tenses in scientific writing

• Present: We study

• Past: We studied

• Present perfect: We have studied

• Future: We will study

Present Tense

• General truths / scientific facts

  Antibiotics resistance is causing a public health crisis.

• Summarise general scope of direction of your paper

  Here we report the discovery of a new cell wall inhibitor.

• Actions / conditions occurring at time of speaking or writing

• Assertions that continue to be true

  The results support the idea that…

Past Tense

• Actions / conditions that occurred at a specific time and do not extend into the present

  We weighed females and randomly assigned them to the experimental treatments.

  Previous studies mentioned vibration of the seahorse’s body.

  Widespread introduction of antibiotics in the 1940s transformed medicine.

• For findings that apply only to a specific study /situation (are not accepted truths)

  Participant 1 reported that exercise reduced her menopausal symptoms.

Present Perfect Tense

• Actions / conditions begun in the past and either completed recently in the past or continuing into the present

  Advances over recent decades have shown that Newton’s laws are inadequate at the atomic scale and at velocities comparable to the speed of light.

• In some cases the meaning of the verb indicates if the action is complete:

  The experiment has begun. (The experiment begun in the past and continuing in to the present)

  The experiment has ended. (The experiment begun in the past and completed recently in the past)

Some grammatical constraints

• Don’t use present perfect when you specify a period of time that is over:

  In 1988, Smith has reported … 💩

  In 1988, Smith reported … 👍

• Don’t use past simple when you specify a period of time that is not over:

  Since 1988, researchers investigated the effects of … 💩

  Since 1988, researchers have investigated the effects of … 👍

Examples

Unemployment leads to poverty. (always true; no beginning or end to it)

Unemployment led to poverty. (true only in this study)

Unemployment has led to poverty. (became true only recently and continues to be true)

Punctuation

Punctuation replaces signals we give when we speak.

Or required by convention (comma after “e.g.” in the middle of a sentence)

Rules of punctuation change over time

Comma ,

After each item in a list of 3 or more

Parkinson’s disease is characterized by muscular rigidity, resting tremor, the slowing of movement, and the blunt affect of its patients.

To separate coordinate adjective before nouns (even if only 2).

• If not coordinate, do not use a comma.

We were prepared for a long, tedious, planning session.

Scientists found evidence of a specialised breather devices called a hepatic piston.

Before and after “non essential” elements

• not essential to defining the words/phrases they refer to.

Several sources of error, which may or may not have altered the results, will be eliminated in the next trial.

Fish which live at a depth of 1000m experience 100 atmospheres of pressure. —> Some fish experience 100 atmospheres of pressure.

Fish, which live at a depth of 1000m, experience 100 atmospheres of pressure. —> All fish experience 100 atmospheres of pressure.

To separate two independent clauses joined by a coordinating conjunction (and, but, or, nor, for, yet, so)

• one independent clause, no comma necessary

The group obtained proof of the substance’s chemical composition, but too little crystalline powder was present to use in the experiment.

Aluminium is the third most abundant element in the earth’s crust and has many important uses in our economy.

Don’t use to separate subjects & verbs / verbs & objects

Developing effective therapies depends on understanding the genetic changes.

After (some) introductory phrases

In nine cases, the people were infected by the virus.

When feeding, a shark often mistakes undesirable food items.

Don’t use too many commas: make the sentence too slow

Semi-colon ;

To join independent clauses without coordinating conjunction

Otherwise, hydrolysis may occur near the top of the solution, where the substrate was added; thus, the absorbance read will not reflect the real rate of activity.

To separate complex list items that contain commas

We tested SR141, a CB1 receptor antagonist; AM630, a CB2 receptor antagonist; and naloxone, an opioid antagonist.

To separate long items in a list (comma could also be used).

Colon :

Use after an independent clause

Introduce a list, explanation, definition

The drugs were: SR141, naloxone, and AM230.

Don’t use to join two independent clauses (use a semi-colon)

Don’t use to break continuing statements

Don’t use after “such as”, “especially”, and “including”

C3 plants function in the following manner: carbon dioxide diffuses from the air, where it is abundant, to the leaf, where it is scarce.

Parenthesis ( )

To separate information that is extra information

• Explanation can be word, phrase, or sentence

Sentence is grammatically complete without the text in ( )

Give the reader permission to skip over the material

Using a standardized fishing technique, we studied sublethal (blood physiology and reflex impairment assessment) outcomes of fishing stress.

Apostrophe '

Only use for indicating possessive

The possessive of it is an exception to the rule

• “it’s” stands for it is or it has

  It’s been (it has been) a long time since I’ve seen you.

  The dog wagged its tail.

A greenhouse is a glass building used to grow plants. A greenhouse has transparent glass that allows the sunlight to pass through but does not allow the heat inside to escape. The same effect occurs on the earth. The sun’s radiation passes through the atmosphere to heat the earth’s surface. When heated, the earth’s surface produces infrared radiation, which has a longer wavelength than that of sunlight. This infrared radiation rises into the atmosphere where gases, such as carbon dioxide, prevent the infrared radiation from escaping into space. The concentrations of these gases, which are called greenhouse gases, control how much infrared radiation escapes. The retained radiation heats the earth’s atmosphere, thus keeping the planet warm.