通过对地下水物理性质的研究，我们能初步了解地下水的( )。A．(A) 形成环境、污染

M: The taxi driver must have been speeding.
W: Well, not really! He crashed into the tree because he was trying not to hit a box that had fallen off the truck ahead of him.
Q: What do we learn about the taxi driver().

A. He turned suddenly and ran into a tree.

B. He was hit by a fallen box from a truck.

C. He drove too fast and crashed into a truck.

D. He was trying to overtake the truck ahead of him.

下面关于下列现象的解释中正确的是（　　）

A．俗话说“铁比棉花重”是因为铁的重力比棉花大

B．抛出去的篮球在空中继续飞行，是因为受到惯性力的作用

C．小孩从滑梯上自行下滑，是因为他受到地球的吸引力

D．书本静止在课桌上，是因为书本的重力与书本对桌面的压力平衡

乙肝患者的肝细胞病变主要取决于（）

A.感染的HBV是否变异

B.感染HBV的数量

C.感染的HBV的亚型

D.感染HBV的途径

E.机体的免疫状况

以下关于粘结力的说法哪项是错误的（）

A.与粘固剂厚度成反比

B.与粘固剂稠度成正比

C.与粘结面积成正比

D.与技术操作有关

E.与粘接剂性能有关

扩散的机制主要有哪几种？