BEFORE plus a verb

[anglychanin.livejournal.com]

I'm a bit confused about "before", especially when a verb comes after

""Before you start off, fasten your seat belt"

"Before you criticise your colleague, you should look in the mirror"

"Before taking off, make sure the aeroplane has some fuel in the tanks"

This is a long standing problem for me. I usually turn the sentence into something else that I do know how to say.

I'd be grateful for a few examples.

(no subject)

[beltspinner.livejournal.com]

Can someone explain to me the difference between the following ways of expressing obligation? I got yelled at in class on Tuesday for not understanding, and I still just don't see understand when one is used against another.

что + обязанность + кого/чего
что + входит в обязанности + кого/чего
что + ябляется обязанностю + кого/чего


Second question:
How do you make verbs into nouns? For the above constructions we're working on, we have to say something like "Reading is the responsibility of a student". I just never learned how to make these constructions.

Thanks