Question 28·Easy·Form, Structure, and Sense
During the annual Science Fair, students displayed models of the solar system, each carefully labeled, thereby ______ their understanding of planetary orbits.
Which choice completes the text so that it conforms to the conventions of Standard English?
For questions testing Standard English conventions, first identify the structure around the blank—look at punctuation and linking words like "thereby" or "which." Decide whether the blank needs a full clause (with its own subject and verb) or just a phrase (like an -ing form or infinitive). Then quickly classify each answer choice by its verb form and eliminate any that cannot grammatically or smoothly fit that structure. When you’re down to two, reread the full sentence with each option and choose the one that sounds natural and maintains clear, standard sentence structure.
Hints
Look at the words around the blank
Focus on the comma and the word "thereby" right before the blank. Ask yourself: is the sentence starting a new idea, or explaining the result of the action just mentioned?
Think about sentence structure after a comma
After a comma and a connector like "thereby," does English usually repeat the subject with a full new verb, or does it often attach a shorter phrase that depends on the previous subject?
Check what can follow "thereby"
You want a word form that can describe the result of the students’ action without needing a new subject. Test each option in the sentence and listen for which one sounds like a smooth, attached result phrase rather than a new sentence.
Use process of elimination
Cross out any choices that sound like they would need their own subject (like "they") or that create an awkward or wordy phrase after "thereby." See which remaining choice fits naturally.
Step-by-step Explanation
Understand the role of "thereby"
"Thereby" means "by that" or "as a result of that." It links the first action (displaying models) to its result (showing understanding). After "thereby," we usually do not start a new full sentence; instead, we add a phrase that describes the result of the previous action.
Decide what kind of word or phrase is needed
Look at the structure:
"...students displayed models of the solar system, thereby ______ their understanding of planetary orbits."
After the comma and "thereby," there is no new subject. So the blank should be filled with a phrase, not with a full standalone verb that needs its own subject. In Standard English, this is typically a verb in its -ing form, used as a participial phrase to describe the result of the earlier action.
Classify each answer choice by verb form
Now see what kind of verb form each option is:
- "demonstrate" = base form (simple present, needs a subject like "they demonstrate")
- "demonstrating" = -ing form (present participle/gerund), which can start a phrase
- "demonstrated" = simple past (would normally need a subject or helper verb)
- "to demonstrate" = infinitive, often used to show purpose ("to demonstrate their understanding...")
Only the -ing form naturally fits as a phrase after "thereby" without adding a new subject.
Choose the verb form that fits the structure
The only choice that works as a result phrase after "thereby" and correctly continues the sentence is "demonstrating":
"During the annual Science Fair, students displayed models of the solar system, each carefully labeled, thereby demonstrating their understanding of planetary orbits."