【单选题】根据实验统计,当操作开关时,其不稳定状态的时间大约会持续( )
【单选题】去甲肾上腺素激活α2受体后引起舒张效应的部位是
【单选题】______ her address, we had great trouble ________ her house.
D.
Haven’t known; to find
【简答题】We can’t write to Mary unless she tells us her address. 转换为if...not
【简答题】Not(know) ______ her address, we couldn't get in touch with her.
【单选题】根据实验统计,当操作开关时,其不稳定状态大约持续多久 ?