她会给小提琴上弦.She can string a violin.该给表上弦了.It's time to wind your watch.上弦月是新月和满月的中间状态.A first - quarter moon is halfway between new moon and full moon....
放大器自激振荡的频率就取决于流体的速度.Amplifier self - oscillates at a frequency depending on the velocity of the fluid.我们从经验观点来介绍运算放大器.We will approach the op - amp from an empirical point of view.它是三极管放大器的等效电路.It is the equivalent circu...