粮食铁路运输不准进行延伸服务和运输代理,不准价外收费,不准()。
A、变更到站
B、使用集装箱运输
C、迂回运输
D、换票运输
参考答案:D
某导体电阻为R,若它两端的电压为U,通过的电流为I;当它两端的电压变为2U时,则通过它的电流I',电阻R'分别为[ ]
A.I'=2I,R'=R
B.I'=2I,R'=2R
C.I'=I,R'=R
D.I'=I,R' =2R
- You talk so much about London. You ________have been there.
- Yeah, I went sightseeing on a tour last summer.
A.must
B.can
C.will
D.need