我国现行饮用水卫生标准(2006)规定,细菌总数应为()
A.<1000个/ml
B.<100个/ml
C.<50个/ml
D.<10个/ml
E.<3个/ml
参考答案:B
She's wearing _____________ red and yellow skirt. [ ]
A. a
B. an
什么叫功能性细胞外液和非功能性细胞外液?