Only when his mother arrived ___________.

      A. the boy stopped crying                            B. stopped the boy crying

      C. the boy did stop crying                            D. did the boy stop crying

 The rest of the apple _________.

      A. were throwing away                                B. was throwing away

      C. were thrown away                                   D. was thrown away

_______ his research, man can set foot on the moon now.

      A. Because               B. Thanks to                C. So as to                 D. In addition to

It is _____ that Professor Smith will give us a lecture tomorrow.

      A. possibly                B. probably                  C. likely                     D. maybe

 His _____ expression suggests that the news he read just now must be _____.

      A. excited; exciting                                        B. excited; excited

      C. exciting; exciting                                       D. exciting; excited

 There was a time _____ hunger was a disturbing problem in this area.

      A. how                       B. when                        C. that                      D. why

. ______ hard. You are sure to succeed!

      A. Working                B. Work                        C. Worked                D. To work

 I regret ______ you that you will miss your flight if you don’t hurry up. You have only twenty minutes to go.

      A. to tell                   B. telling                       C. having told          D. to telling

 The rice made _____ possible to produce one-third more of the crop in the same field.

      A. that                       B. this                          C. one                       D. it

 No one is allowed ______ in the classroom.

      A. smoking               B. smoke                      C. smoked                 D. to smoke