1、我的书比你多 / 比你少
可以说 I have more books than you. / I have fewer books than you.
可以说I have boos more than you. / I have books fewer than you. 但是不常用.
2、你最害怕的动物是什么?
可以翻译为What animals are you afraid of most?.
也可以翻译为What animal are you scared of most?
what后面用animals 和animal 都可以,前者表示那些动物,后者表示哪种动物
best（well 的比较级）和most（much 的比较级）都可以表示程度,前者是褒义词,后者是中性词.
3、你最害怕做什么事情 / 你最喜欢做什么事情? (英语翻译谢谢）
What thing(s) do you fear most to do? // What thing(s) do you like best to hear?
What thing(s) are you afraid of most to do? // What thing(s) are you fond of best to hear?
4、你最怕看到的是什么? / 你最怕听到的是什么?
What thing(s) do you fear most to see / to hear ?
What thing(s) are you afraid of most to see / to hear?
5、most 是副词,副词的最高级常常不用the,因此下面的两个句子都可以,但是不加定冠词更符合习惯.
A , Do you know what I am afraid of the most ?
B, Do you know what I am afraid of most?
Do you know what I am most afraid of 说得过去,但不常见.
Do you know what I am afraid of best 在语法没有问题,但不合乎说话人的情感.（见上面说明）
【有些问题颠来倒去其实是同一个意思,这种提问法不好,人们不愿意回答.】