【单选题】When they arrived at the second crossing, they went the wrong ______.
【多选题】下列选项中,()所说不是输电线路纵联差动保护的特点。
【单选题】Look out the traffic when crossing the road.
【简答题】The old lady carrying a basketful of eggs was run down by a taxi when crossing the street.
【简答题】The old man was knocked down by a taxi when crossing the street.
【单选题】____ be careful when crossing the street!
【简答题】阐述普萘洛尔与硝酸酯类联合应用抗心绞痛的药理基础。