道岔辙叉护轨的作用是为了防止车轮进入异线或撞击叉尖。
参考答案:对
All experts agree that the most important consideration with diet drugs is carefully ___ the risks and benefits .
A.weighing
B.checking
C.taking
D.supposing
直肠内镜检查最危险的并发症是
A.直肠出血B.肛门撕裂C.直肠穿破D.内痔出血