请问 ladder spreader 是什么东西这是上下文：Prior to using a step ladder,the following is to be checked:􀂃 the ladder spreader is not damaged or missing and the locking mechanism is operable;􀂃 the ladder spreader has not

请问 ladder spreader 是什么东西这是上下文：Prior to using a step ladder,the following is to be checked:􀂃 the ladder spreader is not damaged or missing and the locking mechanism is operable;􀂃 the ladder spreader has not 英语翻译a fence is 1.5m high and is 1m from a wall.a ladder must start from the ground,touch the top of the fence,and rest somewhere on the wall.Find the minimum length of such a ladder.请问ladder到底是怎么放的OTL. DNA ladder 和DNA maker是同样的东西么 he went down the ladder.哪个是介词? ladder是什么意思? 请问The ladder,however,was so short that it is coudn't reach the girl. 英语翻译请问 Walking under a ladder到底有什么深层含义?好像和迷信有关的. 英语翻译customer shall install cable ways for the supporting structure (hereinafter cable ladder) of cable trays which provide by Indracable ladder怎么翻?Indra怎么翻?cable ladder是用来放桥架的。indra肯定不是因陀罗。 电泳时marker是如何选择的?100bp DNA ladder是指什么? “at the top of the ladder tree” 是“名列前茅”的意思吗 英语翻译社会阶层英语考破了，我们学的是social ladder都没人说。 ladder going up to the sky 请问这句该怎么翻译呢?go是什么意思呢?谢谢. higher up the ladder educational ladder是什么意思 ladder什么意思 ladder climbing是什么意思 fetch a ladder是什么意思 climb the ladder是什么意思