下列有3个自由度的关节是().
A.肘关节
B.膝关节
C.腕关节
D.肩关节
参考答案:B
—My teachers often encourage me ________ more friends but I find it difficult.
—Your teachers’ idea is right. The more friends you make, ________ you will be.
A.to make; the more happy
B.to make; happier
C.making; the happier
D.to make; the happier
咏叹调