胎盘物质交换中最重要的方式之一是（）。
A.单纯扩散
B.主动转运
C.易化弥散
D.细胞吞饮
E.被动转运
参考答案：A
hey, Alice. You___ on the phone a moment ago. But you weren’t here and I took a message for you.
Oh? I was in the library.
A．are wanted
B．were wanted
C．are called
D．have called
质量是1.5kg的水，温度从80℃降低到30℃，求：水放出的热量是多少？[已知：水的比热容等于4.2×103J/（kg•℃）]．
