What do you think ______ an apple ______ to the ground？
| A．cause， to fall | B．to cause， falling |
| C．causing， falling | D．causes， to fall |
Attracting senior citizens, Florida ishome to the largest population of elder Americans．
| A．/; / | B．the; the | C．the; / | D．/ ; a |
--- -When did he get his first novel published?
---- It was in 2008 ____ he was still in high school.
| A．that | B．since | C．when | D．w hich |
Nobody can explain the mystery ____ he suddenly disappeared.
| A．why | B．what | C．whether | D．which |
It suddenly___ to me that we could use the computer to do the job.
| A．stroke | B．occurred | C．happened | D．saw |
Though she _______for a moment, she finally went in and asked to see a dress that was in the window.
| A．dared | B．nerved | C．wondered | D．hesitated |