Going on a trip into space must be quite exciting experience.
| A．/;the | B．the; the | C．the; an | D．/; an |
He dressed up and went to the party as if ___________.
| A．was invited | B．had been invited | C．invited | D．to be invited |
Scientist are not sure about the ___________ of water on the Mars.
| A．occupation | B．existence | C．demand | D．treasure |
Don’t push me! __________ you know the truth right away?
| A．Must | B．Could | C．Might | D．Would |
. He __________ full marks, but he was so careless as to make a spelling mistake.
| A．must have gained | B．can have gained | C．could have gained | D．must gain |
Then I have learned there are a lot of troubles in our lives, but the problem is __________ they control you or you control them.
| A．why | B．whether | C．that | D．what |