—Don’t throw litter around. It _______ terrible in summer.--Sorry, I won’t.
He is a ___________ student, and he always listens to the teachers ___________.
---Would you please drive______? My plane is taking off.----I’d like to, but safety comes first.
-How often do you go to the movies ?-________,but not often.
Why does Liu Tao look all day long?
We __________ used computers many years ago, but now they’re everywhere.