Don't be joking. It's time to your business.A. set outB. take upC. go onD. get down

问题补充：

Don be joking. Its time to your business.

A. set out

B. take up

C. go on

D. get down

答案：

A. set out

(答案→)B. take up

C. go on

D. get down

解析：take up意为“开始做”；set out开始做应用to do；go on应用with表示继续；get down应为to do。