开展维修工作前后必须采取哪些措施？
简述潮流分布的概念。
售房单位未办妥《土地使用权证》、《房屋所有权证》，抵押人应会同贷款行持依法生效的（）办理抵押登记备案手续。 他项权证。 房屋买卖合同。 房产证。 土地使用权证。
If you must land on a beach with an oar-propelled lifeboat through a heavy surf，the recommended method is to（）. keep the bow directly in toward the beach，and tow the sea anchor off the stern。 ride in on the back of a large breaker。 keep the bow into the seas with the sea anchor out over the bow，and row to meet the breaking waves。 head directly into the beach by staying between the crests of the wave。
维修电气设备设施应注意哪些安全事项？
（）是和Active directory有关的。
