He was looking forward to____to the Literature because he was enthusiastic about poems.

B
1) looking forward to中 to 是介词接动词ing形式。
2）admit和allow都是允许的意思，但前者主要用于允许别人干什么，后者却是用于允许自己干什么，如allow me after you“让我走你后面吧”。

looking forward to dong sth

被动语态be+doing，然后再加上词组looking forward to doing sth 就可以了

B >being admitted

1/ 首先句子需用被动态， 确定BD
2、 admit to sth/ allow to do sth
allow to sth 没这个用法. 只能选B了