The Importance of Seeing the Purpose of Grammar

You've got to see the purpose, the reason why a certain bit of grammar is used. I mean perfectly obvious for example why you should use a plural rather than a singular noun. You have to realise that the reason for the passive is that it enables you to talk about an action without having to say who did it. So looking at language in examples and in context does help especially when you realise that a lot of these answers aren't immediately obvious.