Sat语法题求解It underlies the poem that human beings are free to

Sat语法题求解
It underlies the poem that human beings are free to choose and may be blamed for their choices.
A) It underlies the poem ---------->it is a vague pronoun
B) In the poem,they assumed --------------->they is a vague pronoun
C) In the poem,a basic assumption which is made is -------------->无视他
D) It is an assumption that underlies the poem ----------->wordiness
E) The basic assumption of the poem is ---------->this is the correct choice
综上所述,看起来形式主语好像并不是令人满意的用法.但是在下面这一道题中,形式主语成了正确的选项.
第二题（OC3-10-1)
A recent discovery is the finding that people who both drink and smoke blah blah blah than blur blur blur.
A) A recent discovery is the finding that ------------> wordiness
B) A recent discovery came when they learned that ----------> vague pronoun
C) Recently,a finding is that -------------->我选的是这个,但OC解释说这个是 ineffective usage.
D) It has recently been discovered that -----> this is the correct choice
E) It is a recent dicovery that ----------> wordiness