The imperial tombs must have been under the protection of the state government, or they ________ suffered severer damage．

1. A.
   have had
2. B.
   would have
3. C.
   could have had
4. D.
   should have

The imperial tombs must have been under the protection of the state government, or they ________suffered severer damage.

A. have had       B. would have          C.could have had      D.should have

The imperial tombs must have been under the protection of the state government, or they ________suffered severer damage.

A. have had           B. would have        C. could have had             D. should have