从自然界中筛选微生物菌种的方法和步骤。
参考答案：
采样——增菌培养——纯种分离划线涂菌——纯培养——生产性能测定
—It seems that you are really suffering from a bad cold. How long have you been like this?
—Since last week. When the weather turned cold, I ________ more clothes.[ ]
A. haven't put on
B. don't put on
C. hadn't put on
D. didn't put on
成年人体液量约占体重的（）
A.35%
B.45%
C.50%
D.60%
E.65%
