【注意】若不定式为完成式和被动式，否定词应置于整个结构之前： She pretended not to have seen him. 她假装没看见他。 It is nice not to be dependent on others. 不依靠别人是好的。 You were silly not to have locked your car. 你没锁车太傻了。 2. so as to do sth 和in order to do sth 的否定式 对于这两个结构的否定式，通常是将否定词置于不定式符号to之前，而不是置于整个结构之前或其他位置： Study hard so as not to fail the exam. 努力学习，以免 考试不及格。 He came in quietly in order not to wake his wife. 他轻轻进来，以免把他妻子吵醒。 Go in quietly so as not to wake the baby. 进去时不要出声，以免把宝宝吵醒。 Take every precaution so as not to catch cold.采取一切预防措施以免感冒。 We keep the window shut in order not to let the flies in. 我们把窗子关着以免苍蝇进来。 They hid themselves in the cave in order not to be seen by the enemy. 他们躲在洞穴里以免被敌人发现。 Please reply at once in order not to lose this opportunity of a lower price. 请立即回复，以免失去这次低价的机会。 They must have worn gloves in order not to leave any fingerprints. 他们一定戴上了手套，以防留下指纹。 学好英语可以丰富自己的外交能力，可以为以后的 出国留学做准备。但是英语的学习并非三两天就能完成，在学习的过程中要掌握方法，方法用对，才能有效提高学习效率。
【注意】若不定式为完成式和被动式，否定词应置于整个结构之前： She pretended not to have seen him. 她假装没看见他。 It is nice not to be dependent on others. 不依靠别人是好的。 You were silly not to have locked your car. 你没锁车太傻了。 2. so as to do sth 和in order to do sth 的否定式 对于这两个结构的否定式，通常是将否定词置于不定式符号to之前，而不是置于整个结构之前或其他位置： Study hard so as not to fail the exam. 努力学习，以免 考试不及格。 He came in quietly in order not to wake his wife. 他轻轻进来，以免把他妻子吵醒。 Go in quietly so as not to wake the baby. 进去时不要出声，以免把宝宝吵醒。 Take every precaution so as not to catch cold.采取一切预防措施以免感冒。 We keep the window shut in order not to let the flies in. 我们把窗子关着以免苍蝇进来。 They hid themselves in the cave in order not to be seen by the enemy. 他们躲在洞穴里以免被敌人发现。 Please reply at once in order not to lose this opportunity of a lower price. 请立即回复，以免失去这次低价的机会。 They must have worn gloves in order not to leave any fingerprints. 他们一定戴上了手套，以防留下指纹。 学好英语可以丰富自己的外交能力，可以为以后的 出国留学做准备。但是英语的学习并非三两天就能完成，在学习的过程中要掌握方法，方法用对，才能有效提高学习效率。
