sugar (when) mixed with water,dissolves quickly.句子里连词when加上和不加的区别是什么?

题目

sugar (when) mixed with water,dissolves quickly.句子里连词when加上和不加的区别是什么?
还有如下的句子：(if) given more attention,the tree could be gromn better~the secretary worked late into the night,(for)preparing a long speech for the president~句子里有连词和没有连词有区别么?

答案

第一个句子有问题,应该是when sugar is mixed with water,it dissolves quickly.所以加不加加不加WHEN都是错的 下面两句,加不加括号里的词,意思都一样,因为given more attention和preparing a long speech for the president~都在句中做伴随状语,伴随状语既可以表示条件,也可以表示目的,所以IF和FOR要不要都无所谓