Nobody knows for sure how dinosaurs died out 65,000,000 years ago. It _______ because of sudden changes of their living conditions.
| A．must have happened | B．would have happened |
| C．should have happened | D．might have happened |
Please make my excuse at tomorrow’s meeting--- I’ve got too much work _____.
| A．to do to come | B．doing coming | C．to do coming | D．doing to come |
Mr. Smith is _____ a good teacher _____ we all respect.
| A．such; that | B．such; as | C．so; that | D．so; as |
He is a strict but kind-hearted father, ____ the children respect but are afraid of.
| A．/ | B．that | C．for whom | D．one whom |
The cell phone I _______ I_______ is on the back seat of my car.
| A．thought; had lost | B．think; had lost |
| C．thought; have lost | D．think; lost |
He insisted that the sky ____ clear up the following day.
| A．would | B．should | C．／ | D．be |