事前: before the event; in advance ...必须: must; have to; be obliged to ...保持: keep; hold; retain; maintain ...湿: wet; damp; humid脚: role; part; character必须保持: mandatory retention但是我必须保持这权利: but he just kept right on你必须保持衣着整洁: you must keyour clothes clean同时他必须保持他的歌声: and he just kept on singing实验室里必须保持井井有条: a laboratory must be kept in good order标底必须保密: if a tenderer has a base bid price it must be kept secret and confidential必须保留邮寄凭证: for service by post an accepting institution must keethe postal certificate打开之前必须拔掉插头: pull out plug before opening湿湿湿: wet wet wet须经事前核准, 必须先期批准: subject to prior approval蛋白定量之前必须用两种不同的试剂a: reagent a and b龙刀任务之前必须做的任务之一: the grand tree旅客在登机前必须在提包上拴上标签: before going on aboard the plane the passengers attached a tag to their handbags所有产品出厂前必须要经过严格检查: all products have to pass strict inspection before they go out所有产品出厂前必须要经过严格检查172: what's your general impression may i aski'm impressed by your approach to business在星期一之前必须把论文交上来。: papers must be in by monday事前: before the event; in advance; beforehand 事前毫无准备 with no preparation at all; 事前准备好 be prepared beforehand; 未来之事事前有预兆。 coming events cast their shadows before贵族对吃尤其挑剔,必须保证食品店有美味: tasty持湿剂: humectant湿脚气: wet beriberi