下列何药不属于四环素类抗生素：
A．美他环素B．多西环素C．土霉素D．米诺环素E．大观霉素
参考答案：E
Life is a , meet it! Life is a dream, realize it! Life is a game, play it!
A．challenge
B．disaster
C．hardship
D．stage
简述电弧焊质量要求。
