Is it okay to use Verb after "when" and "while"?

Question

For instance, is a sentence like the one below grammatically okay?

"Driving is strictly prohibited while using this medicine"

I have seen people using verb after "while" and "when", and I thought they did not strictly abide by English grammar when they did so. I think I learned somewhere that conjunctions(e.g. while, when, and, etc.) should not be directly followed by verbs because they are connecting independent clauses. However, I began to doubt my own belief because I have found many sentences on newspaper and textbooks using verbs after "when" and "while".

So my question is, Is it okay to use Verb after "when" and "while"? Then, how are "when" and "while" different from the other conjunctions like "and"?

Answer 1

This is an example of a reduced adverbial clause where the subject+be are omitted.

In this case we change conjuction + subject + be + verb+ing to conjuction + verb+ing

Here is an example with when:

• It's not polite to look into your phone when speaking to someone. (when you are speaking)

With while:

• You should watch the road while driving. (while you are driving)