帮忙分析一下语法结构

主要结构：
The expansion of desert （主） is called desertification.

沙漠的扩张就叫做沙漠化。

like conditions into areas where they did not previously exist

此为插入语。like是指The expansion of desert (主）like(就像）conditions into areas （某种环境进入一些地区）

where they did not previously exist 是这个插入语中修饰areas的定语从句，什么areas呢？是从前they（conditions)并不存在的那些地区。

(The expansion主语 of desert like conditions (定语修饰The expansion)into areas(也是定语修饰The expansion )where they did not previously exist(定语从句修饰areas )is called 谓语desertification.主语补足语
desert like应为desert- like中间应有连线号,desert- like做定语修饰conditions 意思是象沙漠一样的环境,整句意思是象沙漠一样的环境扩展到原先没有沙漠的地方称之为沙漠化
你买的可能是盗版书,质量有问题.

the expansion...previously exist这是主语从句，is是谓语。