世界上人口自然增长率最低的大洲是( )
图所示的两个电路中,电源电压相等,闭合开关S,当滑动变阻器的滑片P都向右滑动时,灯泡L1、L2的亮度变化正确的是( )
4.2÷1.4=____
The magazines are _______ easy that the children can read them well.