有不少动词在接不定式作宾语或宾语补足语时，需要省略 to。可以把它们分为几个主要类别。

1. 感官动词

这类动词表示“看、听、感觉”，当它们后面接宾语再接动词时，表示动作的全过程被感知到了，通常省略 to。

• See / Watch / Look at (看)
  • I saw him leave the house. (我看见他离开了房子。)
• Hear / Listen to (听)
  • We heard the birds sing. (我们听见鸟叫了。)
• Feel (感觉)
  • I felt the ground shake. (我感觉地面在震动。)
• Notice / Observe (注意到)
  • Did you notice him enter the room? (你注意到他进房间了吗？)

语法小贴士： 如果把这类句子变成被动语态，to 就要还原回来。

• 主动：I saw him leave. (我看见他走了)
• 被动：He was seen to leave. (他被看见走了)

2. 使役动词

这类动词表示“强迫”或“帮助”别人做某事。

• Make / Have (强迫、让)
  • Make 的语气比较强，带有“强迫”意味。
    • The boss made us work late. (老板强迫我们加班。)
  • Have 比较中性，常表示“安排、让某人做某事”。
    • I’ll have him call you back. (我会让他给你回电话。)
• Help (帮助)
  • Help 是个特例，它后面既可以省略 to，也可以保留 to，意思基本不变。
  • Please help me (to) carry this box. (请帮我搬一下这个箱子。)

3. 情态动词和特定助动词

这些词后面永远跟动词原形（不带 to）。

• 情态动词：can, could, will, would, shall, should, may, might, must
  • You must finish it today. (你必须今天完成。)
• Do / Does / Did (用于强调或构成疑问/否定)
  • I did see him yesterday. (我昨天确实看见他了。)

4. 固定搭配与短语

还有一些特定的动词或短语，习惯上后面跟不带 to 的不定式。

• Why (not) …? (为什么不……呢？)
  • Why not go for a walk? (为什么不去散步呢？)
• Had better (最好……)
  • You had better leave now. (你最好现在就走。)
• Rather than (而不是……)
  • I decided to stay rather than go. (我决定留下来，而不是走。)

总结表格

类别	常见动词/短语	例句
感官动词	see, hear, feel, watch, notice	I saw him cross the street.
使役动词	make, have, let, help	She made me laugh.
情态动词	can, must, will, should 等	You must go now.
固定短语	why not, had better	Why not try it?

记忆口诀

为了方便记忆，你可以参考这个简单的口诀：

“二听三使四见一感帮”

• 二听：hear, listen to
• 三使：make, have, let
• 四见：see, watch, look at, notice
• 一感：feel
• 帮：help (可带可不带)