--- Can you tell me ______ it is from here to the Summer Palace?

---Let me see. It's about 15 minutes' ride.

A．how far

B．how soon

C．how much

D．how long

不属于人体实验的道德原则是（）。

A.知情同意的原则

B.符合科学的原则

C.符合受试者利益的原则

D.实事求是的原则