Questions 19-22 A．Because it is properly c

疟原虫引起发热的物质主要是（）

A.潜隐子

B.潜隐子和代谢产物

C.裂殖子和疟色素等

D.裂殖子和内毒素等

E.疟原虫体和外毒素

皮革制急救药箱

We are not conscious of the extent of which work provides the psychological satisfaction that can make the difference between a full and empty life.

A．to which

B．in which

C．at which

D．by which

如何理解物质运动不灭原理。