英语介词by的用法
by+名词。可用来表方法、方式、手段等。
1、by+the+可数的时间、长度、重量等名词。意为:“按…计算,按…买(卖)”。如:by the pound/ton/yard/meter/dozen/bale/day/month等。
Cleaning women in big cities usually get paid by the hour.(NMET98)城市里的女清洁工通常按小时获得报酬。

In the market,tobacco is sold by the bale,eggs by the dozen and salt by the pound.在市场里,烟叶按捆卖,鸡蛋按打卖,盐按磅卖。
2、by+表示时间、长度、重量等总称的不可数名词(名词前不加冠词)。意为:“按…计算,按…买(卖)”。如:by time/volume/length/weight/height/depth/width/area等。
As we all know,the freight of the luggage is charged by weight.众所周知,行李的运费是按重量计算的。
PET听力需注意关键词汇总
原则1:定义处
we call it... so called... term be defined that is...
原则2:建议意见处
you should, suggest, recommend, tips, advice, had better do, how about, what about, why not, why don’t you, if I were you
how does…sound?