英语中状语和后置定语的区分

英语中状语和后置定语的区分
i visited my tercher in beijing yesterday.这个句子中介词短语in beijing是做后置定语修饰my teacher,还是做状语修饰visit呢?
it kills many people every year worldwide.这个句子中every year是做状语修饰kill的吗?worldwide是做后置定语修饰people的吗?
there is a boy in the classroom .这里的in the classroom 是什么成份?

i visited my tercher in beijing yesterday.这个句子中介词短语in beijing是做后置定语修饰my teacher
it kills many people every year worldwide.这个句子中every year是做时间状语,worldwide作地点状语
there is a boy in the classroom .这里的in the classroom 是做地点状语
状语包括时间,地点,原因等,在句中表示时间,地点等.
定语在句中起到修饰,限定的作用
再问： worldwide为什么不能当作后置定语修饰many people呢？就像people all over the world ，，，，people here。。。也是副词用作后置定语啊