你胆子很大：

you have balls

很有胆子：

big balls

说话！

say something

你怎么不说话了：

why don't you say something?

Cat got your tongue?

给我放下！

put it down（对方已经拿起来的情况）

don't touch it（对方想拿但还没拿起来）

很淡定：

calm as hell

as cool as a cucumber