小题1:It’s hard/difficult to imagine what life will be like without enough water.

小题2:Is this the second country they will visit in Asia?

小题3:Robots can do housework for you unless you enjoy doing it yourself.

小题4:We do some cleaning/sweep the floor every day to/in order to make our classroom as clean as new. 

小题5:We are/were not sure what they were talking about then/at that moment.

题目分析：

小题1:此题考查固定句型结构it is+形容词to do sth表示做某事怎样，考查的动词不定式做主语常用it来代替作为形式主语。

小题2:此题考查含有定语从句的复合句，they will visit in Aisa做定语修饰country。

小题3:此题考查介词unless的基本用法，表示除非怎样。

小题4:此题考查固定短语in order to表示目的。

小题5:此题考查固定短语be sure表示确信或有把握其后常跟从句。

点评：答题前首先要读懂句子，确定要用到的主要单词，固定短语以及句式等基础内容，结合语义确定句子时态，人称和数等问题。