Let me try to explain.
Here's the original sentence:
Quote:
"Employing groundbreaking techniques in alternative medicines, the patient's health improved in a few days."
This above sentence is wrong. It should look like this:
"Employing groundbreaking techniques in alternative medicines,
the doctors saw the patient's health improve in a few days."
Here's how I think through this question:
Step 1: Identify this sentence structure as [DESCRIPTIVE PHRASE], [MAIN SENTENCE].
Within one second, note that the first word "employing" is an -ING verb, so
structurally the word "employing" MUST describe the subject immediately after the comma.
Look at the original sentence.
Based on the sentence structure, "employing" must describe "patient's health." Ask yourself - does this make sense? Does it make sense that "patient's health" was/were employing groundbreaking techniques?
NO! It doesn't.What the sentence is trying to say is that it was the "doctors" who were employing groundbreaking techniques...not the patient's health!
Step 2: Fix the problem We can fix this by positioning the word "doctor" so that it is in the beginning of the main part of the sentence.[/b] Now we ask the question,
who is "employing groundbreaking techniques??" Well, in the corrected version, we see that it is the "doctors" who are "employing groundbreaking techniques"As to your particular question, it seems you are making the assumption that just because you see one verb in the past tense ("saw") that every other verb must automatically be in the past tense as well.
THIS IS NOT TRUE!For example, you don't say "I saw the soldier died." Instead, you say "I saw the soldier die."
The first verb simply sets the time period whereas the second verb is part of the phrase that takes place in the time period set by the first verb.
I explain this better in the past/present/future framework #9 of the GMATPill.But please note that this assumption is not true.
The above steps 1 and 2 alone are good enough to help you answer the question in 20 seconds.