婴幼儿肺炎的高危因素（）
A.营养不良
B.维生素D缺乏性佝偻病
C.低出生体重
D.先天性心脏病
E.免疫缺陷
参考答案：A, B, C, D, E
– I think teenagers should be allowed to meet internet friends alone.
– ________. It’s not safe enough.
A. I disagree B. I think so C. I agree
