下面小编跟大家一起了解大学英语六级基础语法知识感官动词分享，希望对大家的学习有所帮助。
　　基础语法知识：since的四种用法
　　1) since 过去一个时间点(如具体的年、月、日期、钟点、1980, last month, half past six)。
　　I have been here since 1989.
　　2) since 一段时间 ago
　　I have been here since five months ago.
　　3) since 从句
　　Great changes have taken place since you left.
　　Considerable time has elapsed since we have been here.
　　4) It is 一段时间 since从句
　　It is two years since I became a postgraduate student.
　　基础语法知识：感官动词 doing/to do
　　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。