If they what I was saying, they'd know what I was talking about
| A．took the trouble to listen to | B．had trouble listening to |
| C．take the trouble to listen to | D．have trouble listening to |
He appears ______ a long time. He is impatient for my arrival.
| A．to wait | B．to be waiting | C．to have waited | D．to have been waiting |
Every device ______in the plane must be designed and made with great care so as to make sure that nothing goes wrong in operation.
| A．fitted | B．to be fitted | C．fitting | D．being fitted |
He left home early only______he was late as he went a wrong way.
| A．found | B．to find | C．finding | D．being found |
— Beijing or Shanghai? What did you mean?
— We were talking about _______ go to college.
| A．how to | B．where to | C．whether to | D．when to |
When he was a boy, he used to go there and watched _______.
| A．repairing bicycles | B．to repair bicycles |
| C．bicycles being repaired | D．bicycles to be repaired |