he has been working so hard . __________ he could answer such a difficult question. 
#3464
A
No wander
B
No wonder
C
why
D
because
推荐题目
Let’s go to a movie after work, OK?           — _____________
#3194
A
Not at all.
B
Why not?
C
Never mind.
D
What of it?
Can you tell me the way to the post office?         
#24419
A
The person is over there.
B
Sorry, I’m not from around here.
C
I don’t know you.
D
I know your name.
—What about going for a walk?—______.
#1771
A
Go ahead, please
B
Me, too
C
Help yourself
D
Good idea
—You won’t believe it, Sam. I was chosen as an exchange student to China. —Congratulations! ____________ .
#2556
A
That’s something
B
You did a good job
C
That’s all right
D
You got it