[Alex80]

Hello, friends! I have a question about words like after, when and if. Is it correct to answer a question starting with their clause only without the other one.
*When did she know it was a crocodile?
Answer: when she fell into the water.
Or: After her friend saw it.
Instead of saying: she knew it was a crocodile when she fell into the water.
What if the answer was : After seeing the crocodile.
Or: During the research.

[susan53]

All fine. In speech, once something has been said and is "shared" between the speaker and listener, there's no need to repeat it - in fact the conversation would be very unnatural and boring if it was repeated.
The only one I don't like much is "After seeing the crocodile" - but only because After + Verb+ing is slightly too formal for the context. It's common in written English, but when speaking After she saw... would be more usual.

PS. During isn't a conjunction but a preposition

[Alex80]

Many thanks, my friend