The Indians cut notches on a stick to keep count of numbers.印第安人在棒上刻V形 凹痕用来计数.I've bought so many books this year that I can hardly keep count of them.今年我买了很多很多书,连我自己也不知道到底有多少.Keep count of your return visits to our...
进入睡眠状态时，我们的脑电波振幅慢慢变大。As we fall asleep the amplitude of brain waves slowly becomes greater.由于驱动机构的作用,使驱动端的振幅保持不变.The amplitude at the driven end is fixed by the driving mechanism.这样,即使是最强声音的位移振幅,也还是非常小的.Thus the displace...