选择A.
此处where引导的是一个定语从句,在定语从句中充当状语,修饰stage.该句意思是:这个男孩已经到了一点点小事就容易发怒的局面了.
当先行词为example,case,situation,stage,point等词时,都可以用where来引导定语从句,例如:
* After graduation she reached a point in her career where she needed to decide what to do.
* Today,we’ll discuss a number of cases where beginners of English fail to use the language
properly.
* It’s helpful to put children in a situation where they can see themselves differently.
* Later in this chapter cases will be introduced to readers where consumer complaints have
resulted in changes in the law.