I told Sally how to get here, but perhaps I ­­­­_________ for her.

A．had to write it out         B．must have written it out

C．should have written it out  D．ought to write it out

What I need is_____ book that contains ______ABC of oil painting. 

A. a; 不填        B. the; 不填     C. the; an     D. a ; the

It is ____world of wonders, ____world where anything can happen.

A. a; the   B. a; a  C.  the; a   D.  /;/

Over the past decades , sea ice          in the Arctic as a result of global warming .

A. had decreased    B. decreased    C. has been decreasing    D. is decreasing  .

She brought with her three friends, none of ______ I had ever met before.

A. them        B. who        C. whom          D. these

It was a great _____ for him to be pleasant to people he didn't like.

A. attempt       B. trouble       C. power       D. effort

Don’t be______by products promising to make you lose

weight quickly.

A．taken off    B．taken out  C．taken away D．taken in

It was _____back home after the experiments.

A. not until midnight did he go        B. until midnight that he didn’t go

C. not until midnight that he went      D. until midnight when he didn’t go

13．      a reply，he decided to write again.

A．Not receiving         B．Receiving not

C．Not having received    D．Having not received

10. We went through a period _____ communications were very difficult in the rural areas.

A. which    B. whose   C. in which   D. with which