太阳光经过三棱镜后，被分解成各种色光，这是光的 ____现象．将三种色光适当混合产生其它任何色光，色光的三原色分别是 ____、 ____和 ____．

$\frac{1}{3}$的倒数等于（　　）

⑴Doing more exercise is good for health.  ____

⑵I feel cold. I need to wear warm clothes.  ____

⑶You should see a doctor when you are ill.  ____

⑷If you are angry, you'd better take a deep breath and count to ten.  ____

A.

B.

C.

D.