In order to finish the experiment successfully, the professor always _________, for every day the light in his room didn’t go out until 4 a.m.

A．mixed up

B．cleaned up

C．turned up

D．stayed up

根据计算机动画的表现方式，通常可分为二维动画和______两种形式，不同种类其显现的特点也不尽相同。