這個句子真的是沒有必要地復(fù)雜.
句子要這樣分析：
【He divides them up （into）】 【according to】 【what he thinks (they) are】 the several senses of the word.
【He divides them up】 （into） the several senses of the word.
的意思應(yīng)該很清楚.
現(xiàn)在加上從句 【according to】 【what he thinks (they) are】 .
我們可以說 【he thinks】是【according to】 【what he thinks they are】 的插入語.
into 和 they 被省略了.
they 是指 the several senses of the word
希望幫到了你.所以說，①這和what are you doing？ 是不一樣的？what are you doing？的what是作賓語？②he thinks作插入語為什么要選擇放在what后面呢？①這和what are you doing？ 不一樣what are you doing？的what是作賓語。he thinks作插入語要放在what后面，因為是陳述句語序，又如：1 Tell me what you believe he has done to our school's reputation.2Our work is well done according to what everyone here knows is our teacher's smiling face.