_____ his ability of speech, he has made use of each chance.

   A. To improve                B. Improving                C. Being improved        D. Improved

He found that complex problems, especially those _____ abstract thinking, were best for picking out bright and dull students.

   A. involve                   B. involved                C. involving            D. being involved

______ with severe drought in some areas, Chinese government is taking active measures to ensure people’s essential needs.

   A. Facing                          B. Faced                   C. To face               D. Being faced

There is a new problem        in the popularity of private cars        road conditions need to be improved.

A.involving, that    B.involved, that     C.involved, where               D.involving, which

________ the secret of nature, the young scientist has little time for entertainment.

A. Devoted to bring up                        B. Devoted himself to bring up

C. Devoted to bringing up                      D. Devoting to bring up

______ its size with that of the whole earth, we find the highest mountain does not seem high at all.

A.When compared    B.Compared to C.To be compared         D.Comparing

__________ as one of the most talented artist in European history, Van Gogh couldn't have sold a single work without his brother’s assistance.

A. Thinking          B. To be viewed              C. Viewed　　　　　　D. Considering

The comments the expert made ______ stock-market bothered him greatly, ______ him not

fall asleep all night.

A. be concerned, which made                                   B. concerned, making

C. concerning, making                                    D. to be concerning, made

We had an anxious couple of weeks ______ for the results of the experiment.   

       A. wait                 B. to be waiting    C. waited               D. waiting

He called the police for help,       that the problem was more than he could deal with.

       A. having been realized    B. realizing        C. realized     D. had realized