你在干什么？
Nǐ zài gàn shénme?
What are you doing?
你干什么呢？
Nǐ gàn shénme ne?
你这样干什么？
Nǐ zhèyàng gàn shénme?
What are you doing that for?
这东西干什么用？
Zhè dōngxi gàn shénme yòng?
What is this used for?
