帮我修改一下这句话的语法问题what most deserves us to study in history is the method of our predecessor used to deal with the same events what also happen today.

what deserves us to study history most is the method our predecessor used to deal with the very events that sitll happen today.

What deserves us to learn from history most is our predecessor's method of dealing with the same events that are also happening even today.

what deserves us to study in history most is the method (that) our predecessor used to deal with the same events that also happen today.
most这里做状语成分,用来修饰程度的,放在原句的位置上也是可以的,但是从语感角度上说,这样比较好
of是要去掉的,我知道你想用的是of的所有格形式,做定语进行修饰,但是used是谓语动词呀!加上that或者不加,看成是定语从句,先行词是method,that做从句中used的宾语,因而可以省略.
最后的what必须该that,那是定语从句,what不引导定语从句.这是常用考点,切记.