风痧的好发年龄是()
A.1岁以下
B.1~5岁
C.6~9岁
D.9岁以上
E.任何年龄
参考答案:B
There _______ a concert in our city next month.[ ]
A. is going to have
B. has
C. is going to be
D. are
炼钢生产的主要危险源及主要事故类别和原因?