Aluminum lifeboats are subject to damage by electrolytic corrosion (the aluminum being eaten away). In working around boats of aluminum you must be very careful（）. to keep the boats covered at all times。 not to leave steel or iron tools lying in or near these boats。 to keep an electric charge on the hull at all times。 to rinse these boats regularly with salt water。
试阐述水刺缠结的基本原理。
查询省内其他地市登记的企业的巡查记录，可以用下面哪个软件？（） 市场准入。 市场管理。 浙江省数据查询。 基层管理。
选用刺针的原则是什么？
液化天然气（LNG）储罐应（）对储罐的真空度检测一次。 每年。 每半年。 每2年。 每月。
All inflatable liferafts have（）.
