反患者应尽早矫治,治疗不及时可形成Ⅲ类骨性反,其矫治年龄应在()
A.3~5岁
B.6~7岁
C.8~9岁
D.11~13岁
E.18岁以后
参考答案:A
There ______ a football match and a concert this weekend. Which one would you like to go?[ ]
A. is
B. are
C. will be
D. will have
青藏地区之所以能成为一个独特的地区,是因为( )
A.地势高
B.气温低
C.光照强
D.冰川广