I don't know when the bridge was built_______，but it must be very old．（ ）
A．exactlyB．carefullyC．luckilyD．easily
The students were singing happily_________ I passed the school hall．（ ）
| A． |
when |
B． |
unless |
C． |
though |
Eleven Chinese films ___________ during the 7th Chinese Film Festival in France last month．（ ）
| A． |
showed |
B． |
are shown |
C． |
were shown |
﹣_____________ has Hong Kong been back to our motherland？
﹣For 20 years．How time flies!（ ）
| A． |
How soon |
B． |
How long |
C． |
How often |
﹣Nowadays more and more foreigners are becoming interested in Beijing Opera．
﹣That's true．It's an important part of Chinese____________．（ ）
| A． |
culture |
B． |
invention |
C． |
custom |
﹣Mum，may I go swimming now？
﹣Yes，dear，but remember that you___________go with your dad．（ ）
| A． |
may |
B． |
can |
C． |
must |