Does “take a crack at”means “try”？ Does “take a crack at”means “try”？

Does 'pull strings'mean behind the scene? Does 'pull strings'mean behind the scene?

First notebook entry: Introducing myself I'm a Chinese girl who want to learn English and make friends here.I like to watch TV and movie,all kinds of those.I have learned English 12 years,I can recognize lots of words and read most of articles but poor on speaking it.