【单选题】冷却系统中锈蚀物和水垢积存的后果是( )。
【判断题】直流发电机在电枢绕组元件中产生的是交流电动势,只是由于加装了换向器和电刷装置,才能输出直流电动势。
【单选题】I did not want to be responsible for Mable insomnia , so I kept the three dollars,
【简答题】He is a boy of quick _______.
【简答题】The boy is a quick learner. The boy learns ________________________