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.(强调"我见他正干活"这个动作)

昨天我见他正在花园里干活。

典型例题

1)They knew her very well. They had seen her ___ up from childhood.

A. grow B. grew C. was growing D. to grow

答案：A。因题意为，他们看着她长大，因此强调的是成长的过程，而非正在长的动作，因此用see sb do sth 的句型。

2)The missing boy was last seen ___ near the river.

A. playing B. to be playingC. playD. to play

答案A. 本题强调其动作，正在河边玩，应此用see sb. doing sth句型。