Sentence Structure

By Xiaochi Liu in Scientific Writing

Express the core of the message in the subject, verb, and completer

Sentences tell us

  • who is the sentence about

  • what did they do

Make the topic the subject of the sentence

The topic is what the sentence is talking about

The children had diabetes mellitus.

The children with arteriovenous shunts had the shunts opened, heparin injected, and the arterial and venous sides of the shunt clamped. 💩

In the children who had arteriovenous shunts, the shunts were opened, heparin was injected, and the arterial and venous sides of the shunt were clamped. 👍

Put the action in the verb

The action is what the topic is doing / being done to it

We performed an analysis on the data. 💩

We analysed the data. 👍

Verbs are action words: describe motion (e.g., explore, examine, observe)

Verbs can be turned into noun

verb noun
to regulate regulation
to occur occurrence
to understand understanding
to investigate investigation
to complete completion

  • Readers expect the main action of a clause to be found in the verb

  • Many nouns that express action are made by addition of a noun ending to a verb

  • Another verb must be added

    • vague & don’t express action

    • occurred, was seen, was noted, was observed, caused, produced

      An increase in heart rate occurred.

      Heart rate increased.

      The new drug caused a decrease in heart rate.

      The new drug decreased heart rate.

      With leg vessel congestion, the compliance of forearm vessels increased significantly.

      When leg vessels were congested, the compliance of forearm vessels increased significantly.

Avoid starting with “there is”

There is inhibition of the immune system.

The immune system is inhibited

Sentences are easier to read when the ratio of Verbs:Nouns is higher

An increase in heart rate occurred. (1:2)

Heart rate increased. (1:1)

The new drug caused a decrease in heart rate. (1:3)

The new drug decreased heart rate. (1:2)

Verbs in noun form can sometime be useful (increase cohesion)

  • can summarize the action of the previous sentence

  • form a backward link to something familiar (increase cohesion)

Action in the verb examples:

They had resolution of their arthritis.

Their arthritis resolved.

We made at least two analyses on each specimen.

We analysed each specimen at least twice.

The patient showed no change in symptoms.

The patient’s symptoms did not change.

The patient’s symptoms were unchanged.

A progressive decrease in death rate occurred.

The death rate progressively decreased.

The death rate decreased progressively.

The database has been subject to different improvements.

The database has been improved.

Keep subjects near verbs

Reader looks for two primary piece of information

  • Who is the sentence about?

  • What are they doing?

Confuses reader if far part. Reader will need to re read the sentence

Farmers that understand the difference between the soil requirements of plants when they are seedlings and their requirements when they are mature are in high demand. 💩

Farmers are in high demand if they understand the difference between the soil requirements of plants when they are seedlings and their requirements when they are mature. 👍

One study of 930 adults with multiple sclerosis (MS) receiving care in one of two managed care settings or in a fee for service setting found that only two thirds of those needing to contact a neurologist for an MS related problem in the prior 6 months had done so (Vickrey et al 1999). 💩

One study found that, of 930 adults with multiple sclerosis (MS) who were receiving care in one of two managed care settings or in a fee for service setting, only two thirds of those needing to contact a neurologist for an MS related problem in the prior six months had done so (Vickrey et al 1999). 👍

Give the context before you write a list

Peanuts, shrimp, almonds, milk or anything else with lactose, and wheat or anything with gluten all represent things that people are commonly allergic to. 💩

People are commonly allergic to peanuts, shrimp … 👍

Avoid noun clusters

blood flow, protein metabolism, lung function, filament length variability

Noun clusters dilute the meaning

Long noun clusters bring imprecision into sentences

Solar One is a 10 megawatt solar thermal electric central receiver Barstow power pilot plant.

Solar One is a solar powered pilot plant located near Barstow.

Solar One produces 10 megawatts of electric power by capturing solar energy in a central receiver design.

To untangle noun clusters:

  • start at the end

  • work to the beginning

  • adding prepositions

filament length variability

variability of the length of the filaments

variability of filament length

To untangle adjectives and noun clusters:

  • start at the end

  • work to the beginning

  • adding prepositions

  • place adjective in front of appropriate noun

  • only one noun should be placed after the adjective

Chronic sheep experiments

Chronic experiments in sheep

Peripheral chemoreceptor stimulation

Stimulation of peripheral chemoreceptors

Revised version is longer than original version - clarity, not brevity

Treat noun clusters like abbreviations

  • Avoid if possible.

Write short sentences

Short sentences are easier to understand

  • Don’t pack too many ideas into one sentence

  • Don’t string ideas together

  • Don’t talk about more than one thing at a time

Mean sentence length < 22 words

  • Balance longer sentences by writing a short sentence

  • Short sentences have strong impact

  • Important ideas in the short sentence

Sentences vary in length

  • Short sentences:

    • introducing a new subject

    • making an impact

    • striking conclusion

  • Long sentences:

    • developing a point

Use clear pronouns

A word that replaces and refers to a noun

  • it, he, she, they, these, those, them, this, that, which, both

We use these conditions because they allow us to measure the ….

The noun that the pronoun refers to needs to be clear

Research on these diseases is hampered because laboratory animals are not susceptible to them.

Avoid having an unsupported “this”

  • This/these + a summary phrase (unattended this common in spoken and informal writing)

  • Avoids ambiguity

  • Is an empowering device (allows writer to interpret the prior information)

Put parallel ideas in parallel form

Parallel ideas

  • Ideas that are equal in logic and importance

  • Joined by and, or, but

  • Comparisons

Use same grammatical structure

  • Clauses (subject, verb, completer)

  • Prepositional phrases (of, in, for)

  • Infinitive phrases (to determine, to identify)

Readers can concentrate all their attention on the relation of the ideas

  • similarity

  • alternatives

  • contrast

  • comparison

Cardiac output decreased by 40% but there was only a 10% decrease in blood pressure. 💩

Cardiac output (subject) decreased (verb) by 40% (completer) but blood pressure (subject) decreased (verb) by only 10% (completer). 👍

We hoped to increase the complete response and improve survival.

We hoped to increase the complete response and to improve survival.

This lack of response could have been due to damage of a cell surface receptor by the isolation procedure, but it could also be that isolated cells do not respond normally because the cells are isolated.

This lack of response could have been due to damage of a cell surface receptor by the isolation procedure, but it could also have been due to isolated cells not responding normally because they are isolated.

Overuse of “compared to”

  • when writing higher, greater, less, afterwards write than (not compared to)

    We found a higher number of bacteria at 37° than at 25°

  • “Compared to” should not be used with “decreased” or “increased” because the meaning is ambiguous.

    The experimental wheel had a 28% decrease in turning resistance compared to the current standard wheel on indoor surfaces.

    • Did turning resistance decrease (A) in both the experimental and standard wheel? (B) only in the experimental wheel? (C) in neither type?

    The experimental wheel had a 28% greater decrease in turning resistance than did the current standard wheel.

    The experimental wheel had a 28% decrease in turning resistance but the current standard wheel had no decrease.

    The experimental wheel had a 28% lower turning resistance than did the current standard wheel.

Problems with Comparisons

  • Overuse of “compared to”

  • Comparing unlike things. Don’t try to compare apples and pears

    These results are similar to those of previous studies.

  • Absolute statements disguised as comparisons

    In this medium, the concentration of phosphate (4-5 mM) is about half that in Schneider’s medium (9-10mM).

Examples

Even the highest dose of atropine had no effect either on the baseline pulse rate or on the vagally stimulated pulse rate.

Cardiac output was less in the E.coli group than in the Pseudomonas group.

The tubes were spun on a Vortex mixer for 10s, stored at 4° for 2h, and then they were centrifuged at 500g for 10 min.

An impulse from the vagus nerve to the muscle has to travel both through ganglia and though post-ganglionic pathways.

Left ventricular function was impaired in the dogs that received endotoxin but not in the control dogs.

The mechanical response of heart muscles depends both on the absolute osmolal increase and on the species studied.