A:There is no point
B:There is no need
C:It is no wonder
D:It is no way
如图所示,在磁铁正上方用弹簧挂着一条形磁铁,开关闭合后,当滑片P从a端向b端滑动过程中,则电流表的示数____ ,弹簧的长度将____ (选填变小、不变或变大).
It is ____(polite) to stare at others in public places.
下列能够正确表示蛙的发育过程的是( )