When and where he came here _______ yet.
| A．isn’t known | B．aren’t known | C．has not known | D．have not been known |
The best moment for the football star was ______ he scored the winning goal.
| A．where |
| B．when |
| C．how |
| D．why |
______ the forest park is far away, a lot of tourists visit it every year.
| A．As |
| B．When |
| C．Even though |
| D．In case |
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 |