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%