溶解氧、磷酸根、氯离子、钙离子是反映水中某种（）的成分指标。
A、技术
B、杂质含量
C、人为拟定
D、胶体
参考答案：B
Mother likes _______ . Look! She _______ now.
A．shopping, shops
B．to shop,shopping
C．shop, is shopping
D．shopping, is shopping
正常情况下皮肤表面细菌寄生部位不包括()
A．外耳道
B．口腔
C．毛囊
D．甲床
