【简答题】有一只额定电压U N 为100V,额定功率P N 为60W的白炽灯泡。拟将它接于电压U为220V、频率f为50Hz的交流电路使用,为此在电路中串联了一个电感线圈。问这个线圈的容许电流和电感值L各为多少?(电感线圈的电阻可以忽略)。
【单选题】The post card is sent by ____.
B.
a friend of my father's
【判断题】循环系统是进行血液循环的动力和管道系统,由心血管和神经系统组成。
【判断题】循环系统是进行血液循环的动力和管道系统,由心血管和神经系统组成。
【简答题】Want to say 'hello' from Disneyland? Send a post card! Beautiful scenes of paradise (乐园), wild animals, silly pictures — you can find them all in one place. Where? On a post card! Have people always s...
【单选题】听力原文:Do you remember how to get to the post office from here? (A) To buy a post card. (B) Yes, it's not that far. (C) It'll be a little late. (10)
【单选题】There is a picture _____________ the post-card. [ ]