求详细解释SAT语法题（10月28）

求详细解释SAT语法题（10月28）
1.To insist that a poem means whatever A.( one ) B.( wants it ) to mean is often C.( ignoring ) the intention and D.( even ) the words of the poet.
2.At a time A.( when ) interest in twentieth-century classical music B.( seems) on the verge C.( to disappear ),the avant-grade compositions of the 1960s and 1970s D.( manage ) to retain their popularity.
3.He was the author whom I believed was most likely to receive the coveted award.
为什么不能用whom呢?
4.Thompson's fictional retelling of Ignaz Semmelweis's battle to eradicate childbed fever proved to at least one adolescent reader that ( taking a stand against the establishment,no matter the consequences,is worth the struggle.)
A.taking a stand against the establishment,no matter the consequences,is worth the struggle
E.taking a stand against the establishment,irregradless of the consequences,is worth the struggle
为什么不选E呢?