【简答题】重结晶是用于____物质提纯的一种实验操作。
【多选题】工业化道路的问题,主要是指( )的关系。
【单选题】The sales manager was so adamant about her idea that it was out of the question for any one to talk her out of it.
【单选题】The question set by the teacher was so difficult that the pupils did not know how to it.
【单选题】在生物安全柜内操作需移动多种物品时,应按照( )