①血浆中溶菌酶的杀菌作用属于人体的第一道防线 ②抗原都是外来异物
③人体分泌的乳汁中含有某些抗体 ④吞噬细胞可参与特异性免疫
⑤过敏反应一般不会破坏组织细胞 ⑥HIV主要攻击人体的T细胞，引起自身免疫病．
A：2
B：3
C：4
D：5
情绪与情感并没有什么区别。你如何看待这种说法？
Lin Hai is ____ years old. His father is a police officer. ____is very busy, but he____his ____. Sometimes he works day and night. Sometimes he works ____holidays. He doesn't ____much time to ____with his son. Lin Hai is very proud of his ____.
下列气体通入水中，水溶液呈碱性的是（ ）
