有这样一道语法考题，该用动词原形？还是用非谓语动词？
_________ the road round to the right and you’ll find his house.
A. Follow B. Following C. To follow D. Followed
【分析】此题容易误选B或C，许多同学一看选项就想当然地认为，选现在分词表示时间或伴随，选不定式表目的。此题的关键是要注意句中的连词and，它表明整个句子是一个并列句，即 and 前后应各是一个独立的句子，而不应是一个非谓语形式的短语，所以此题的正确答案应选A，即 and 前是一个祈使句。比较以下两题：
(1) _________ the road round to the right, she found his house.
A. Follow B. Following C. To follow D. Followed
【分析】此题应选B，现在分词短语表时间。
(2) _________ the road round to the right, the blind man asked a boy to guide him.
A. Follow B. Following C. To follow D. Followed
【分析】此题应选C，不定式短语表目的。
注意以下各题均应选A，均因为句中的并列连词 and(填空句为祈使句)：
(1) _________ the milk and set a good example to the other children.
A. Drink B. To drink C. Drinking D. Having drinking
(2) _________ me, and don’t just stand there laughing.
A. Answer B. To answer C. Answering D. To be answering
(3) _________ me , and then try to copy what I do.
A. Watch B. Watching C. To watch D. Have watching
(4) _________ through this book and tell me what you think of it.
A. Look B. Looking C. To look D. Having looked
(5) _________ it with me and I’ll see what I can do.
A. Leave B. Leaving C. If you leave D. When left
注：有时可能不用连词，而用破折号(答案均选B，填空句为祈使句)。如：
(1) _________ down the radio — the baby’s asleep in the next room.
A. Turning B. Turn C. Turned D. To turn
(2) _________ some of this juice — perhaps you will like it.
A. Trying B. Try C. To try D. Having tried
以下各题也应选A，是因为句中的从属连词 when, before, until 等(填空句为祈使句)：
(1) _________ left when you get to the end of the street.
A. Keep B. Keeping C. To keep D. Kept
(2) _________ you hand over your mouth when you cough.
A. Put B. Putting C. To put D. To be putting
(3) _________ him enough time to get home before you telephone.
A. Give B. To give C. Giving D. Given
(4)_________ until the lights have turned to green.
A. Wait B. To wait C. Waiting D. Having waited
(5) _________ 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，即填空句为祈使句：
(1) Don’t give me a long account, just _________ the plain facts.
A. tell B. telling C. to tell D. to be telling
(2) First _________ the rice by washing it, then _________ it in boiling water.
A. prepare, cook B. preparing, cooking C. preparing, cook D. prepare, cooking
(3) Don’t sit there watching — _________ and help me!
A. come B. coming C. to come D. to be coming
(4) Don’t waste your money on silly things — _________ it.
A. save B. to save C. saving D. having saved
(5) 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，以下各题情形有所不同，所填部分为目的状语(用不定式，即答案均为B)：
(1) _________ late in the morning, Bob turned off the alarm.
A. Sleep B. To sleep C. Sleeping D. Having slept
(2) _________ the early bus, Mr Smith got up at six.
A. Catch B. To catch C. Catching D. Having caught
