鼻咽癌最常见的病理类型是()。
A.高分化鳞癌
B.腺癌
C.低分化鳞癌
D.泡状核鳞癌
E.未分化癌
参考答案:C
The poor man stood there, with his hands ____, ____ his eyes upon the dark cave.
A.crossed, fixing
B.crossing, fixing
C.crossed, fixed
D.crossing, fixed
起重机在1min内将重为5000N的重物匀速提升36m,求:
(1)起重机对重物所做的功为多少;
(2)起重机的功率及重物上升的速度.