钢管脚手立杆必须垂直，要设有扫地杆，杆件搭接必须用回转扣件或直角扣件扭牢，不得松动。
参考答案：错
Food, ______ and shelter are the three most necessary things for people to depend on.
A. clothes B. clothing C, cloth D. dress
下列各项，不属桔梗的主治病证是（）
A.肺痈
B.咳嗽
C.咽痛
D.痰证
E.眩晕
