二、宾语从句常用引导词：that,what, which, who, how, whether, if

that在名词性从句中只负责把从句引出来，不在从句里充当成分，这点和在定语从句里的用法不同，定语从句中that充当成分；

what一般不用于定语从句，用在名词性从句里既引导从句，又在从句充当成分；

which在名词性从句里含有“哪一个”的意思，通常有一定的选择范围，而在定语从句里则没有意思，只是引导句子和充当句子成分；

who在从句里充当成分，指人，不指物；

how表示“如何”，可以用来表示程度；

whether表示“是否”，不管是主语从句，表语从句，宾语从句里都可以使用；

if用法比较复杂，有多种限制，而且雅思里例句出现非常少；

三、剑桥真题例句：

1. We have found  that  the blind understand other kinds of visualmetaphors as well.(C4T2P3P28L7)

2. Long before peopletravelled to America or anywhere else, they knew  what   other places looked like; they knew  how otherpeople worked and lived. (C6P63L48)

3. Because we watchthem so closely and because everybody in the world seems to know  who  they are, they appear more real to us than wedo ourselves. (C6P64L3)

4. They and the othermonkeys must be followed still longer, however, to know   whether  low-calorie intake can decrease both averageand maximum lifespans in monkeys. (C6P72L9)

5. They then had tojudge  which  they preferred.(C11P49L16)

6. Because differentobservers can have different ideas of  what  constitutes, for example, an open snowdrop. (九分达人1P10L30)