液压防喷器开关动作时，所需液控压力油来自（）。
A、电泵
B、气泵
C、储能器
参考答案：C
—Would you like to attend China's Got Talent (中国达人秀)?
—_________ But I'm busy revising for my test.[ ]
A. Don't mention it.
B. I'd love to.
C. That's all right.
D. My pleasure.
简述维果斯基关于教学与发展的关系。
