急性失血时，最先出现的调节反应是（）

A.血管的自身调节

B.交感神经兴奋

C.迷走神经兴奋

D.血中血管升压素增多

E.血中血管紧张素Ⅱ增多

Have you ever _____ playing in front of thousands of people at a concert?

A．dreamed

B．imagined

C．pretended

D．wanted