by有以下幾種用法：1.表示“在……旁邊，從……旁邊”；2.到（某時候）；3.由(被)(某人干的)；4.以(某種方式)；5.乘坐(車、船等)；6.在(本性、職業(yè))上等用法。

by的用法和例句：

1)在……旁邊，從……旁邊：

Come over here and stand by me．
過來站在我旁邊。

He put it on the table by the window．
他把它放在窗邊的那張桌子上。

He passed by me without noticing me.
他從我身旁走過，但是沒看到我。

2)到（某時候）：

Perhaps she has recovered by now．
現在她或許已經痊愈了。

The sun had set by this time.
到這時太陽己經落山了。

Just be here by eight．
八點前到這里。

3)由(被)(某人干的)，主要用于被動語態(tài)：

The postman was bitten by the dog．
郵差給狗咬了。

Who is that book by?
這書是誰寫的?

The play was written by a student．
這個劇本是一個學生寫的。

4)以(某種方式)：

We learn to swim by swimming．
我們在游泳中學游泳。

Please let me know by telegram．
請以電報通知我。

Don’t judge a man by his clothes．
不要以衣著判斷人。

5)乘坐(車、船等)：

I came by bus(subway)．
我是坐公共汽車(地鐵)來的。

We are going by the 9：30 train．
我們坐九點二十的火車去。

I prefer to go by plane(boat)．
我寧愿坐飛機(船)去。

6)在(本性、職業(yè))上：

She is generous by nature．
她天生很慷慨。

He was tolerant by temperament．
他性格很寬容。

I am not an actor by profession．
我不是職業(yè)演員。

7)by表示程度尺寸等：

Total commodity stocks grew by 4.5 per cent．
商品總庫存量增長了百分之四點五。

Fares have been increased by 10％．
票價上漲了百分之十。

The room is thirty feet by twenty．
這間房長二十英尺，寬二十英尺。