—I’m busy with my schoolwork these days.—That’s great! You won’t get good grades ______ you work hard.
#35791
A
if
B
because
C
unless
D
after
推荐题目
The train is going _______ the tunnel. Then it will go ______to the center of the city.
#36769
A
through; towards
B
through; straight 
C
across; towards
D
across; straight
John often goes to school _____.
#41114
A
by foot
B
on foot
C
on feet
D
by feet