A.水質(zhì)不良B.補(bǔ)水未除氧C.補(bǔ)水未除氯D.水溫低
A.地面不平B.轉(zhuǎn)動設(shè)備防護(hù)罩不完善C.欄桿缺失D.光線暗淡
A.沿水溝B.巖層松動的山坡C.沿圍墻D.沿道路