The new invention may __________a lot of changes in our daily life.

A. result from          B. expose to                    C. lead in                   D. contribute to

Dr. Black is a professor of chemistry. _______, he is a famous writer.

A. In all                           B. In brief                         C. In fact                   D. In addition

---How long has the United Nations ________?

   --- ______1945.

A. come into existence; In          B. been in existence; Since

C. been in existence; From          D. come into existence; For

Would you please ______ your statement again? I don’t understand what you were saying.

A. classify                 B. clear           C. clarify            D. charity

The girl looked at me with a _______expression. Maybe the problem was quite ______.

A. puzzled; puzzling               B. puzzling; puzzled     

C. puzzled; puzzled                      D. puzzling; puzzling

On hearing the bad news, he got up quickly ______ the lunch unfinished.

A. leaving                      B. left                          C. to leave             D. leave

By the time we reach that page, we ___________ twenty lessons of the book.

A. will study       B. will have studied        C. would study      D. have studied

Everyone has periods in their lives ______ everything seems very hard.

A. when          B. where               C. which             D. that

The boy suggested that Tom ______ the problem another way, and Tom’s expression suggested that he_________.

A. should solve; agreed    B. solve; agree      C. solved; should agree   D. solved; agreed

Electric trains have now _______ steam trains in England.

A. taken place       B. in place of      C. instead of      D. taken the place of