在思维创新过程的有关研究中，沃拉斯所提出的思维创新过程分为（）阶段。
A.准备期
B.酝酿期
C.豁朗期
D.验证期
参考答案：A, B, C, D
Though Lei Feng ________ for fifty years, we are still learning from his spirit.
A．has died
B．died
C．has been dead
D．had died
充油设备渗漏率按密封点。不能超过（）。
A、0．1％
B、0．05％
C、0．02％
D、0．01％
