如图所示,图甲中把装满水的玻璃杯盖上纸片倒置过来,纸片不下落,此现象说明__________;图乙中的“手影”现象说明光在空气中是________传播的。
大气压的存在;沿直线
测量蓄热室吸力,当某一次交换完毕10min后,开始插管测量。
.
When he was young, he used to __________ hard at his lessons.
A.devote to working
B.devote himself to work
C.be devoted to work
D.be devoted to working