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Fireworking Posted 14 years ago
Vocabulary

"Just by" vs "Just

Hello, I am preparing for the SAT and I can't wrap my head around this one question.

This is a sentence correction question. I have shortened the question to only include the parts I am confused about. The underlined oart pf the sentence should be replaced by ( A) or ( B).

Just by swishing water in your mouth when you are finished eating or drinking helps avoid tooth decay.

( A) Just by swishing water in your
( B) Just swishing water in your

B is the correct answer. The question is why is A is incorrect. It seems that both would be correct (but understanding the nature of the test, A is automatically incorrect).

Thanks for your help! I really appreciate it.
  

Top answer

X helps avoid tooth decay. X is the subject and must be a noun or noun-form. mouth' is a prepositional phrase ('by' is a preposition), which is not a noun form.

  • X helps avoid tooth decay.
  • X is the subject and must be a noun or noun-form.
  • mouth' is a prepositional phrase ('by' is a preposition), which is not a noun form.
  • mouth' is a noun phrase headed by the gerund 'swishing'.
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2 Answers
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X helps avoid tooth decay.

X is the subject and must be a noun or noun-form. ' (just) by....mouth' is a prepositional phrase ('by' is a preposition), which is not a noun form. '(Just) swishing...mouth' is a noun phrase headed by the gerund 'swishing'.
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Awesome! Thanks for the clear explanation!

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