You never imagine what trouble I have had ______ your house．It took me nearly 2 hours．
| A．to find | B．finding |
| C．found | D．for finding |
The famous basketballer, _______ tried to make a comeback, attracted a lot of attention.
| A．where | B．when |
| C．which | D．who |
I saw some trees the leaves of _____ were black with disease.
| A．that | B．which |
| C．it | D．what |
Their problem today is somewhat similar to _____ they faced many years ago.
| A．that | B．which |
| C．that which | D．it |
Dorothy was always speaking highly of her role in the play, ____, of course, made the others unhappy.
| A．who | B．which |
| C．this | D．what |
He made another wonderful discovery, ______ of great importance to science.
| A．which I think is | B．which I think it is |
| C．which I think it | D．I think is |