引導名詞性從句的連線詞可分為五類：
a.連詞：that（無任何詞意，不作成分，只起連線作用，賓語從句中常可省略）
1) my hope is that she will soon be well again. (表語從句)
我的希望是她能很快康復。
2) everybody hopes that she will soon be well again.（賓語從句）
大家都希望她能很快康復。
3) that she will soon be well again is our hope.（主語從句）
她能很快康復是我們的`希望。
b. whether, if（均表示“是否”表明從句內容的不確定性，不作成分）
1) whether he is coming or not doesn’t matter too much.(主語從句，不能用if)
2) i went in and asked if/whether they had a cheap suit.
3) i wonder whether/if he will come in such bad weather.
c. 連線代詞：what, whatever, which, whichever, (在從句中作主語，賓語，表語，指物)
1) ____he need is more time.
顯然，主語從句：he是主語，謂語動詞need缺賓語，因此應填what.
2) tell us ___you saw and heard during your visit to that university.
3) this is not ___i want.
4) ____some people are against is ___other people are for.
5) the question is which team will win.
6) i have two apples, i don’t know which you want.
歸納：what一般用於不知道內容或範圍的句子；which“哪一個……”一般用於給出內容或範圍的句子。可作主語，賓語，表語，還可作定語。
d. who, whoever, whom, whomever, whose（在從句中作主語，賓語，表語，定語，指人）
1) who will give us a lecture is unknown.
2) the question is who will come here.
e. 連線副詞：when, where, how, why, whenever, however, wherever (在從句中作狀語)
1) i have no idea how he learned about it.
2) where she has gone is not known yet.
3) when he will start is not known yet.
4) this is why he is late.
注意：連線代詞和連線副詞在句中既保留自己的疑問含義、又起連線作用，在從句中充當從句的成分。
