Whether life will continue on the earth for millions of years ______will depend on ____this problem can be solved.
—Is your mother still a teacher? —______.
—Shall I go and buy two more bottles of beer? —No, I’ve already bought twenty. That ___ be enough for us two.
.—Did you visit the museum? —No, we ____ it, but we spent too much time shopping.
Crusoe had to stay in cave, ___ go out, even for food.
If you want to borrow a football after school, your student ____ here.