When I try to find ______that prevent so many people from taking part in the program, it seems to me that there are two main causes.
| A．why it does | B．what it does | C．what it is | D．why it is |
Jamaican Usain Bolt was reported ______the world record of 100m in 9.69 seconds, thus winning his first gold medal.
| A．breaking | B．having broken | C．to be broken | D．to have broken |
If it _______ next week , the crops would be saved.
| A．rains | B．will rains | C．would rain | D．should rain |
Not only ______ prepare lunch for us, but also _______ clothes for us.
| A．he did , he washed | B．he did , did he wash |
| C．did he , he washed | D．did he, did he wash |
You must read the _______ with great care to see if the drug contains PPA before it is taken.
| A．instructions | B．introductions | C．explanations | D．Expressions |
I ____ too much reading.
| A．am tiring | B．tired out because of | C．am tired out in | D．tired myself out with |