The students were ________ over the ________ problem，listening to the teacher with a ________ expression on their faces.
| A．puzzled；puzzling；puzzling | B．puzzled；puzzling；puzzled |
| C．puzzling；puzzling；puzzled | D．puzzling；puzzled；puzzling |
Their belief is proved by the fact that the death penalty prevents murder.
| A．that | B．which |
| C．what | D．the fact that |
What he said at the meeting referred to _______ he was interested in the project.
| A．that | B．which |
| C．what | D．the fact that |
She must face up to _______ she is no longer young.
| A．that | B．which |
| C．what | D．the fact that |
They knew nothing about ______ he was a thief.
| A．that | B．which |
| C．what | D．the fact that |
We were all worried over _______ you were sick.
| A．that | B．which |
| C．what | D．the fact that |