Question

If the students who killed themselves had only been more confident, their deaths ________.

1. A.
   need have been avoided
2. B.
   must have been avoided
3. C.
   might have been avoided
4. D.
   will have been avoided

Answer 1

C
might have done，对过去的虚拟。“他们的死可能会被避免”，their deaths与avoid之间为动宾关系，因此选C。