________, the boy couldn't enter his house.
| A．Since the key has lost | B．The key been lost |
| C．Lost the key | D．Having lost the key |
Books of this kindwell．
| A．sell | B．sells | C．are sold | D．is done |
.He was removed from the company，for he couldn’this way of life to the rest．
| A．match | B．fit |
| C．suit | D．adapt |
Although he is always coming on time，he is usedlate for his class.
| A．to have students | B．for students’ being |
| C．to students’ being | D．for students’ to be |
Although the causes of cancer ____we do not yet have any practical way to prevent it.
| A．are being uncovered | B．have been uncovering |
| C．are uncovering | D．have uncovered |
These wild flowers are so special that I would do ____I can to save them.
| A．whatever | B．that | C．which | D．whichever |