French language Q&A Forum

Another problem I have here is with the explanations in the lesson. It says that when talking about SOMETHING SPECIFIC, you should use elle/il. But then there's this example: Qui est Sylvie ? - C'est ma sœur. 

I would think that here we are talking about a very specific Sylvie, and not just some Sylvie. Then why do we say c'est instead of elle? 

When I did a test, I answered one wrong because the correct answer was;

Nous ne savons pas ce qui tu fais

Could you please explain this?

In a quiz I was asked to translate "My aunt drives as carefully as my uncle" and I responsed with "Ma tante conduit aussi prudemment que mon oncle". Why did Kwiziq mark this wrong and want "document"? Aren't both of these equally valid translations?

And this lesson does not even use the word doucement, which might have indicated that Kwiziq perferred that word.

Searching on the web provides thousands of instances of "conduire prudemment" with the meaning of carefully.

"Nous irons visiter We'll go and visit."

I would translate this to English as "We'll go to visit." Would that also be "Nous irons visiter " in French.