I can’t remember __________  you started to do the work.
A  when it was that      B  when was it that
C  it was when             D  that it was when

___ he will come or not is_____ worries us.

.It was obviously that the man ______ driving on the free way for almost an hour when he ______ that he must come back.

The audience, ________ , enjoyed the performance.

. ______ is no possibility _____ Jack will win the first place in the competition.

________________________, and the problem would be straightened out（解决）.

____________, I wouldn’t have finished my homework.

Further space exploration has been _______ with the rapid development of China’s science and technology.

—What about putting some pictures into the report？
—      A picture is worth a thousand words.

Carl Linnaeus made great contributions to ________ plant species.