题目内容：

it is obvious to the students ------they should get well prepared for their future.
a.as b.which c.whether d.that
as不是可以相当于前面所讲的东西吗?为什么不能用as

优质解答

d.that
it is obvious ……that是一个句型
it 做形式主语,真正的主语是that后面的
as 可以指前面讲的东西,但是,意思是正如……
在这里不符合

追问：

it is obvious ……that什么意思

追答：

……很明显；显而易见的是……