读东南亚图，回完成下列问题：
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.
关于x的一元二次方程x2+a=0没有实数根，则实数a的取值范围是____
