Though I have often heard this song _______. I have never heard you _______ it.
| A．being sung, sang | B．sang, singing |
| C．sung, sing | D．to be sung, to sing |
The father as well as his three children___skating on the frozen river every Sunday afternoon in winter
| A．is going |
| B．go |
| C．goes |
| D．are going |
In that school,French and Russian are optional,but English is___for all students
| A．special |
| B．regional |
| C．compulsory |
| D．original |
Not only___the data fed into it,but it can also analyze them
| A．the computer can memorize |
| B．can the computer memorize |
| C．do the computer memorize |
| D．can memorize the computer |
___so as to make our city green
| A．It is necessary to plant more trees |
| B．Many trees need to be planted |
| C．Our city need more trees |
| D．We must plant more trees |
___prevent cheating,the test questions are kept secret
| A．So as to |
| B．In order that |
| C．In order to |
| D．So that |