主語從句有以下連接詞及其用法：
1.That
That matter takes up space is known to all.(= It is known to all that matter takes up space.)
2.whether (if)
Whether she is will join us doesn't matter too much.(=It doesn't matter too much whether (if) she is will join us.)
3.what
What is to be done next hasn't been decided yet.(= It hasn't been decided yet what is to be done next.)
4.which
Which test is to be made first remains to be discussed further.(= It remains to be discussed further which test is to be made first.)
5.who
Who will head the delegation is unknown.(= It is unknown who will head the delegation.)
6.whoever
Whoever will go may sign here.
7.whatever
Whatever steps you take should be practical.
8.whichever
Whichever comes in first will receive a prize.
9.what(so)ever
What(so)ever we do must benefit the people.
10.whichever
Whichever you want is yours.
11.When,where and how we are to go is still a mystery.(= It is still a mystery when,where and how we are to go.)
12.Why she is absent this morning hasn't been clear.( =It hasn't been clear why she is absent this morning.)