Carl is starting college in September. ______, he’s traveling around Europe.
| A．Therefore | B．Meanwhile | C．Though | D．However |
This is a very interesting book. I’ll buy it,__.
| A．how much may it cost | B．no matter how it may cost |
| C．however much it may cost | D．how may it cost |
The two biologists debated ____each other for years ______ the origin of species.
A. with; about B. about; for C. between; over C. to; for
John rushed out in a hurry, ___________ the door ____________.
| A．leaving; unlocked | B．leaving; unlocking |
| C．left; unlocked | D．sang; singing |
Mrs. Brown was much disappointed to see the washing machine she had______went wrong again.
| A．it repair | B．it repaired | C．had repaired | D．to be repaired |
---What is our earth like ________from the moon?
---Well, our earth, with water ________ 70% of its surface, appears as a "blue ball".
| A．seen; covering | B．seen; to cover |
| C．seeing; covered | D．seeing; covering |