We shou
ld not let our grandparents who are too old and weak ________ alone.
| A．live | B．living. | C．to live | D．lived |
If you want to see a doctor, fix the date with him ahead of time. This is a common ___________ in the USA.
A. habit B. law C. rule D. custom
I can't make a decision now. I need _________ more time to think it over.
| A．rather | B．fairly | C．quite | D．lot |
with the size of the whole earth, the highest mountain doesn't seem high at all.
| A．When compared | B．To compare |
| C．While comparing | D．It compared |
He is believed____________ in at his office on his way home.
| A．dropping | B．to have dropped |
| C．having dropped | D．to be dropped |
—What would you wish to do if you were a college student again?
—That's very hard to say, but I wish I when I was a college student.
| A．has not studied biology | B．did study biology |
| C．had studied biology | D．studied biology |