【简答题】He never forgot the hardships he witnessed during the Great of the 1930s.(depress)
【简答题】三相异步电动机为什么能采用变频调速?在调压过程中,为什么要保持u比f比值恒定?普通交流电机变频调速系统的变频电源主要由哪几部分组成?其主电路目前采用哪些类型的半导体组件?
【简答题】A.evolve B.assemble C.betray D.depress
【简答题】He never forgot the hardships he witnessed during the Great _______ (depress) of the 1930s.