The city government decided to keep the old temple for its historical_____.
| A．price | B．cost | C．value | D．usefulness |
There are still many problems ______ before we are ready for a long stay on the Moon.
| A．solving |
| B．solved |
| C．being solved |
| D．to be solved |
______ I have a word with you? It won't take long.
| A．Can |
| B．Must |
| C．Shall |
| D．Should |
I borrowed the book Sherlock Holmes from the library last week, ______ my classmates recommended to me.
| A．who |
| B．which |
| C．when |
| D．where |
Last night, there were millions of people ______ the opening ceremony live on TV.
| A．watch |
| B．to watch |
| C．watched |
| D．watching |
______ carefully if any change occurs when doing experiments in the lab.
| A．Observe |
| B．To observe |
| C．Observed |
| D．Observing |