A:枢(shū)纽粗犷(kuǎng)茅塞(sè)顿开
B:管辖(xiá)惘(wǎng)然泰然处(chǔ)之
C:愠(wèn)色冰窖(jiào)停滞(zhì)不前
D:附和(hè)造诣(yì)华陀再见(jiàn)
如图所示,将截面为正方形的真空腔abcd放置在一匀强磁场中,磁场方向垂直纸面向里.若有一束具有不同速率的电子由小孔a沿ab方向射入磁场,打在腔壁上被吸收,则由小孔c和d射出的电子的速率之比____;通过磁场的时间之比为____.
This boy is Peter .He is from America.He is ten years old . His hair is yellow.Peter can play basketball. This is his school.It's very big. There are forty students in his class. Miss White is his English teacher. Peter is good at English.
如图所示的四种家用电器中,利用电流热效应工作的是( )
化学与生产、生活、社会密切相关。下列说法中不正确的是