处于较高能态的分子返回到基态时便发出相应光谱称()。
参考答案:发射光谱
________ the past, leaving the sadness behind, _____ you’ll see the door of a new bright world open before you.
A.Forget; and
B.Forgetting; and
C.Forget; /
D.To forgetting; /
T系列交流伺服电机为实心轴电机。