One-third of the country ______ covered with trees and the majority of the citizens black people.
A. is; are B is; is C are; are D are; is
The train was to arrive at 11：30，but it was an hour late．
| A．about | B．likely | C．certain | D．supposed |
According to the air traffic rules，you should your mobile phone before boarding．
| A．switch over | B．switch on | C．switch off | D．switch round |
After he retired from office，Rogers painting for a while，but soon lost interest．
| A．took up | B．took off | C．took down | D．took in |
Months ago we sailed ten thousand miles across this open sea，which the Pacific，and we met no storm．
| A．was called | B．is called |
| C．had been called | D．has been called |
My little son used to drink a lot of fruit juice but these days he mineral water．
| A．prefers | B．is preferring | C．preferred | D．had preferred |