1. Why，you may wonder，should spiders be our friends?
你可能会觉得奇怪， 蜘蛛怎么会是我们的朋友呢？
you may wonder插入语，是独立的成分，不具有语法意义，去掉后也不影响句子的完整性。
2. Insects would make it impossible for us to live in the world.
昆虫就会使我们无法在地球上生活下去。
make宾语补足语
最常见的使役动词有：make，have，leave。他们都表示“使得”，后面都可接宾语 宾语补足语的结构，但用法上有所不同。
make用作使役动词表示“使；使成为”时，可跟复合结构，即“make 宾语 宾语补足语”，其中的宾语补足语可以是形容词或名词、不带to的不定式、过去分词。
（1）我们推选他为我们足球队队长。
We made him captain of our football team.
（2）我们队赢了的消息使我们大家非常高兴。
The news that our team had won made us very happy.
（3）大雨使得我们无法出去。
The heavy rain made it impossible for us to go out.
注意：过去分词作make的宾语补足语时，变为被动语态不用加to；但当不定式作其宾补时，变为被动语态一定要加to。
这个男孩被迫每天干十二个小时的活。
The boy was made to work twelve hours a day.
3. they would devour all our crops and kill our flocks and herds, if it were not for the protection we get from insect-eating animals.
要不是人类受一些食虫动物的保护，昆虫就会使我们无法在地球上生活下去，昆虫会吞食我们的全部庄稼，杀死我们的成群的牛羊。
if it were not 虚拟语气
if it were not for…与现在事实相反， if it had not been for与过去事实相反，两个都相当于but for：
If it had not been for his help(=but for his help), we would not have succeeded.
