关于脑脊液哪项不对()
A.成人总量约120~150ml
B.脑蛛网膜下隙约35~40ml
C.脑室约60--70ml
D.脊蛛网膜下隙约25~30ml
E.终池约10ml
参考答案:E
We'll get there at eight, but they _____.[ ]
A. aren't
B. didn't
C. won't
D. don't
图所示的是某型号电热水壶铭牌,壶中装有1.8L温度为20℃的水,求:
(1)将水烧开,水吸收的热量是多少?〔一个标准大气压下,c水= 4.2×103J/(kg·℃) 〕
(2)若在电热水壶工作时,标有“3000r/kW·h”的电能表在1min内转了50转,电路的实际电压是多少?
(3)不计热损失,此时烧开一壶水大约需要多少时间?