在AT89S51单片机中，若采用6MHZ晶振，则机器周期为（ ） A: 166.7ns B: 116.7us C: 2us D: 2ms

Are there enough books for ____? A: three us B: us three C: all us D: the three us

______ agrees to your plan. A: Anyone of us B: No one of us C: None of us D: Someone of us

Mr. Yang ______. A: teaches math us B: teaches us to math C: teaches math to us D: us teaches math

What does sleeping help us? A: It helps us stay healthy. B: It helps us improve our memory. C: It helps us reduce stress. D: It helps us lose weight.

Miss Li is ______ English teacher. She likes______ very much. A: our, we B: our, us C: us, our D: us, us

The new washing-machine has been______. A: giving us trouble B: getting us trouble C: asking us trouble D: looking for us trouble

The teacher told us that Tom us for America．

Any delay in the shipment would ______. A: cause us in inconvenience B: involve us in much inconvenience C: involves us in convenience D: involve us inconvenience

某商店销售的100种主要商品今年上半年与去年同期相比，销售额增长了12%，价格下降了4%，则商品的销售量总指数为（）。 A: 112% B: 16.7% C: 116.7% D: 107.7%