We will fail the exam____we study hard．
That's why we are trying our best to prepare for the exam．（ ）
A．untilB．whenC．unlessD．how
Guizhou is ______ Huanguoshu Waterfall and Moutai in the world.（ ）
| A． |
famous for |
B． |
popular with |
| C． |
regarded as |
D． |
As we all know，the telephone ________ by Alexander Graham Bell in 1876.（ ）
| A． |
invented |
B． |
is invented |
| C． |
was invented |
D． |
Jimmy wants to _______ his trip because he is too busy with his studies.（ ）
| A． |
put off |
B． |
wait for |
| C． |
prepare for |
D． |
In order to protect the environment，many people choose to go to work _____ subway.（ ）
| A． |
in |
B． |
on |
C． |
by |
Jason will go to visit his grandparents ________ he finishes his work this weekend.（ ）
| A． |
unless |
B． |
though |
C． |
if |