在封闭式制冷螺杆压缩机中，油还作为电动机的（）。
参考答案：冷却液
哮喘最常见的外因是（）
A.宿痰
B.过食生冷
C.感受外邪
D.阳虚痰凝
E.暴受惊恐
I took them _____ because I didn't know which was the best.
A．neither
B．nobody
C．no one
D．all
