如图4所示，甲是一个带正电的小物块，乙是一个不带电的绝缘物块，甲、乙叠放在一起静止于粗糙的水平地板上，地板上方空间有水平方向的匀强磁场
Most Americans get what money they have from their work; that is, they earn an income from wages or salaries．The richest Americans, however, get most of their money from what they own ------- their
如图表示的是纯净物、单质、化合物、含氧化合物、氧化物之间的包含与不包含关系，若整个大圆圈代表纯净物，则在下列选项中，能正确指出①、②
She told Tom ________ make the same mistake again. A. he can’t B. don’t to C. to not D. not to
23．下面是某高校新生入学报到流程图，请用文字转述新生报到流程，要求简洁、明了。
屠呦呦因发现对抗疟疾的青蒿素而获得．2015年的诺贝尔生理学或医学奖．青蒿素的化学式为C15H22O5，它在湿、热条件下易分解．下列说法正确的是（
The manager had fallen asleep where he ____, without undressing. A.was laying B. was lying C. had laid
下列四组生物中，都属于真核生物一组的是 A．噬菌体和根霉 B．细菌和草履虫 C．蓝藻和酵母菌 D．苔藓和变形虫
