Whether he agrees or not，I shall do that. 不管他同意與否我都要做這事。

（4) whether可以引導(dǎo)主語從句、表語從句、同位語從句，接不定式．或接or not等（if則不能）

Whether he will come or not is unknown. 還不知道他來不來。（主語從句）

The question is whether it is worth doing. 問題是這件事是否值得去做

I have no idea whether he is there. 我不知道他是否在那里（同位語從句）

I don‘t know whether he will do it or not. 我不知道他是否會(huì)做這事。（接or not)

She hasn‘t decided whether to go or not，她還沒有決定去還是不去。（接不定式）

六、知識(shí)*能力聚焦

1. by prep.

(1)表示“相差”，指增加或減少的程度

The water level of the lake was going to rise by 63 metres.湖里的水位要升高63米

We defeated the opposing team by 3 runs (by a score of 5 to 2 )．我們以3分的優(yōu)勢（5比2)擊敗對(duì)方

(2)表示單位，“以……計(jì)、依據(jù)”( by后面的名詞之前通常一要加定冠詞）

I‘m paid by the hour．我是按時(shí)計(jì)酬的

Is this cloth sold by the metre?‘這塊布是按米出售的嗎？

We can buy the eggs by the dozen.我們可以按打買雞蛋

(3)by還可用于表達(dá)其他意義．

There is a tree by the water.水邊有棵樹（指離水近）

They are coming by the highway．他們正沿公路而來

I took your pen by mistake．我錯(cuò)拿了你的鋼筆

The pool is 15 meters by 50 meters.這個(gè)游泳池長50米，寬15米、

Keep close by，or you will get lost.跟近一點(diǎn)，否則你會(huì)迷路的

What time is it by your watch？你的表幾點(diǎn)了？

Have you read any books by Lu Xun?你讀過魯迅寫的書嗎？

The children went in two by two.孩子們兩個(gè)兩個(gè)地進(jìn)來了