1. 不定式的否定式的構(gòu)成
通常是將否定詞not或never置于不定式之前，即構(gòu)成not to do 或never to do 的形式，注意not和never一定要放在不定式符號to的前面，而不是其后面：
The doctor advised me not to smoke. 醫(yī)生勸我不要抽煙。
It’s politically short-sighted not to do so. 不這樣做在政治上是短視的。
He strongly advised me not to do so. 他使勁勸我別這樣做。
Take care not to break it. 小心別把它打破了。
Be careful not to break anything. 當(dāng)心別打破什么了。
She had sense enough not to say anything about it. 她有足夠的頭腦不提此事。
Father warned me never to drive after drinking. 父親警告我不要酒后開車。
Visitors are requested not to touch the exhibits. 參觀的人請勿觸摸展品。
【注意】若不定式為完成式和被動式，否定詞應(yīng)置于整個(gè)結(jié)構(gòu)之前：
She pretended not to have seen him. 她假裝沒看見他。
It is nice not to be dependent on others. 不依靠別人是好的。
You were silly not to have locked your car. 你沒鎖車太傻了。
2. so as to do sth 和in order to do sth 的否定式
對于這兩個(gè)結(jié)構(gòu)的否定式，通常是將否定詞置于不定式符號to之前，而不是置于整個(gè)結(jié)構(gòu)之前或其他位置：
Study hard so as not to fail the exam. 努力學(xué)習(xí)，以免考試不及格。
He came in quietly in order not to wake his wife. 他輕輕進(jìn)來，以免把他妻子吵醒。
Go in quietly so as not to wake the baby. 進(jìn)去時(shí)不要出聲，以免把寶寶吵醒。
Take every precaution so as not to catch cold.采取一切預(yù)防措施以免感冒。
We keep the window shut in order not to let the flies in. 我們把窗子關(guān)著以免蒼蠅進(jìn)來。
They hid themselves in the cave in order not to be seen by the enemy. 他們躲在洞穴里以免被敵人發(fā)現(xiàn)。
Please reply at once in order not to lose this opportunity of a lower price. 請立即回復(fù)，以免失去這次低價(jià)的機(jī)會。
They must have worn gloves in order not to leave any fingerprints. 他們一定戴上了手套，以防留下指紋。
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