I can't use your pen, ___ there is no ink in it.
| A．for | B．when | C．if | D．whether |
________ on ten years of observation and study, Professor Wang announced that everyone dreams every night，whether they realize it or not.
| A．Basing | B．Based |
| C．Been based | D．Having based |
The air has leaked out of this football.Could you get it ________ up?
| A．blow | B．blowing | C．blown | D．to blow |
________ the right decisions ________ the future is probably the most important things we'll ever do in our lives.
| A．Making；concerned | B．Made；concerning |
| C．To make；concerned | D．Making；concerning |
—What do you think made Celia so happy?
—________a prize in the recent competition.
| A．As she won | B．Won |
| C．Winning | D．Because of winning |
The wrong you have done to him is terrible，________， in my opinion，you should apologize to him.
| A．which | B．that |
| C．what | D．for which |