28. Dr. Frank failed many times but he finally _____ to find a successful way to solve the problem.
| A．broke off | B．broke up | C．broke down | D．broke through |
They might just have a place ___ on the writing course ---- why don’t you give it a try?
| A．leave | B．left | C．leaving | D．to leave |
Most of these groups _______ teachers and graduate students, but some freshmen join as well.
| A．make up | B．is made up |
| C．consist of | D．is consist of |
If _______ to look after luggage for someone else, inform the police at once.
| A．asked | B．to ask | C．asking | D．having asked |
Laura was away in Paris for over a week. When she got home, there was a pile of mail _______ for her.
| A．waited | B．to wait | C．waiting | D．was waiting |
Just tell me the accident to the point, but don’t ______ any important detail.
| A．let out | B．figure out | C．leave out | D．give out |