Question

If ____ unsolved, the problem of food safety may lead to more serious results.

1. A.
   making
2. B.
   remained
3. C.
   left
4. D.
   taking

Answer 1

C
考查省略句。The problem与leave构成被动关系，使用过去分词。完整的结构应该是If the problem is left unsolved, the problem of food safety may lead to more serious results.句意：如果这个问题被留在没有被解决，它会导致更严重的后果。