严重低钾血症病人主要死于（）
A.心肌收缩性降低
B.心肌传导性降低
C.心肌自律性降低
D.肾功能严重障碍
E.呼吸衰竭
参考答案：E
all the students went to Beijing for a visit, we couldn't find anyone in our classroom. [ ]
A．Because; so
B．Because; but
C．Because; /
N15型平车标记载重量为（）。
A、60t
B、6lt
C、63.2t
D、65t
