____several times，but unfortunately，the boy still couldn’t smooth away the problem on his own.
| A．Having been explained | B．The problem having been explained |
| C．The problem had been explained | D．Although the problem had been explained |
The official________I thought would be seriously punished received a raise instead.
| A．whomever | B．whoever |
| C．who | D．whom |
—What are they up to？It’s so noisy.
—Some students________a party.
| A．have had | B．are having |
| C．had had | D．were having |
Fully________to looking after three children at home，she no longer has time to enjoy the various activities in the club.
| A．attached | B．occupied |
| C．contributed | D．devoted |
—Is the letter from your mother?
—Yes.But she ________the letter herself，because she doesn’t even know one word.
| A．needn’t have written | B．can’t have written |
| C．might not have written | D．should not have written |
With the loss of labor，the old farmers ________at home had to choose less laborintensive crops.
| A．having left | B．to leave |
| C．left | D．leaving |