_______ he has made a decision, it is not easy for you to make him change his mind.
| A．Though | B．Unless | C．Once | D．Until |
I found the lecture hard to follow because it ______ when I arrived.
started
B. was starting
C. would start
D. had started
--- What time is it?
--- I have no idea. But just a minute, I ______ it for you.
| A．check |
| B．checked |
| C．will check |
| D．would check |
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 |