Question

Our teacher told us _______ that we never forget it.

1. A.
   so an interesting joke
2. B.
   such an interesting joke
3. C.
   so interesting a joke
4. D.
   such interesting a joke

Answer 1

C
so后面要紧跟形容词，然后再跟名词，如果该名词为可数名词的单数形式，那么要在名词前加不定冠词；such要跟名词，如有形容词修饰，且该名词为可数名词单数时，其结构为:such+a/an+adj.+n.。