er做后綴的單詞有：
washer n.洗衣機；
lighter n 打火機；
heater n 加熱器；
boiler n 鍋爐；
mutter v 喃喃自語；
chatter v 喋喋不休；
stutter v 口吃；
waver v 擺動；
batter v 連打，不斷打。
例句：
The singer was discovered while still at school.
這個歌唱家在上學的時候就受到賞識了。
The star of the show was a young Italian singer.
那臺節目的主角是一位年輕的意大利歌唱家。
The singer gave a dismal performance of some old songs.
那歌手唱了幾首老歌，唱得不怎么樣。
He won't cut it as a professional singer.
他的歌藝未達到專業歌手水平。
The singer worked hard on the clear articulation of every note.
歌手苦練以便每一個音都唱得清晰。