三） 不定式的省略
1） 感官动词 see, watch, observe, notice, look at, hear, listen to, smell, taste, feel + do表示动作的完整性, 真实性； + doing 表示动作的连续性, 进行性
I saw him work in the garden yesterday.
昨天我看见他在花园里干活了。（强调"我看见了"这个事实）
I saw him working in the garden yesterday.
昨天我见他正在花园里干活。（强调"我见他正干活"这个动作）
感官动词后面接形容词而不是副词：The cake tastes good. It feels comfortable.
2） 使役动词have, bid, make, let 等词后不定式要省略但同1）一样被动以后要还原to
I’d like to have John do it. I have my package weighed.
Paul doesn’t have to be made to learn.
3） help help sb do , help sb to do, help do, help to do
