劳动者以完成一定劳动定额为计酬标准的工作时间制度是
A. 标准工作日
B. 缩短工作日
C. 弹性工作日
D. 计件工作日
This is ________ to students of English.
A. a useful advice
B. useful advice
C. one of useful advices
D. piece of useful advice
Finally Billy got ________ as a waiter in a restaurant.
A. a piece of job
B. a job
C. a piece of works
D. a work