问题
I ___________ frustrated when I wasn’t sure of the correct answer.[ ]
A: may be
B: used to
C: used to be
D: use to be
B: used to
C: used to be
D: use to be
正确答案是：
同类题型
Elephants have their own way to tell the shape of an object and ________ it is rough or smooth.
They are having _______ dinner at home.
I enjoy the popular dance “hip-hop”, but ________of my parents likes it.
_____ do you exercise? — Twice a week.[ ]
John likes Chinese. He learns it______ watching Chinese movies.[ ]