Ⅰ. also较正式,位置通常靠近动词,用于句中;且用于肯定句中。如:
① He also plays football. 他也踢足球。
② I was also there.我也在那儿。
Ⅱ. too 多用于口语,通常置于句末,前边须用逗号隔开,也可用于句中,且前后均须用逗号隔开,;用于肯定句中。如:
① He is a worker, too.
② The two cows, too, are white.那两头奶牛也全都是白的。
Ⅲ. as well 是副词短语,多用于口语,只用于句末。如:
① She not only taught us English but taught us maths as well.她不但教过我们英语,还教过我们数学。
② He is a teacher and a writer as well.他是位教师,也是一位作家。
Ⅳ. either 用于否定句中,常置于句末。在肯定句变否定句时,其中的also, too, as well都要改为either.
① Yesterday I didn’t watch TV and I didn’t see the film, either .昨天我没有看电视,也没有看电影。