是考查祈使句还是非谓语动词

(11)______ until the lights have turned to green.

A. Wait                             B. To wait

C. Waiting                        D. Having waited

(12) ______ the pieces of cloth with a loose stitch before finally sewing them together.

A. Join                              B. To join

C. Joining                          D. Joined

以下各题也应选A，因为填空句为祈使句(from www.hxen.net)：

(13) I don’t want to listen a long story — just _____ me the result.

A. tell                                B. telling

C. to tell                            D. to be telling

(14) Why stand there watching — _____ and help us!

A. come                            B. coming

C. to come                        D. to be coming

(15) Don’t waste your money on silly things — ______ it.

A. save                             B. to save

C. saving                           D. having saved

(16) First ______ the rice by washing it, then ______ it in boiling water.

A. prepare, cook                 B. preparing, cooking

C. preparing, cook               D. prepare, cooking

(17) To test eggs, _____ them in a bowl of water: if they float they’re bad, if they sink they’re good.

A. put                                 B. putting

C. to put                             D. to be putting

但是请注意，类似下面这样的题目情形有所不同，所填部分为目的状语（用不定式，即答案选B）：

(18) ______ French well, she went to France to live with his cousins.

A. study                              B. To study

C. studying                          D. Having studied

(19) _____ late in the morning, Mr. Smith turned off the alarm.

A. Sleep                              B. To sleep

C. Sleeping                          D. Having slept

(20) ______ the flies out, we had to shut all the doors and windows.

A. Keep                              B. To keep

C. Keeping                          D. Having kept

(21) ______ their service, the workers of the hotel are active in learning English.

A. Improving                       B. To improve

C. Improve                          D. Having improved