下列物质中,不属于人体内环境组成成分的是[ ]
A.钙离子
B.葡萄糖
C.血红蛋白
D.激素
答案:C
The speaker announced that there was a big fire and directed _______ nearest the door to leave first. [ ]
A. that
B. them
C. those
D. these
处于市场追随者地位的企业实施的办法有专业化经营被大企业忽视的产品。( )