more much 加比较级

一般形容词的比较级是在后面加er，harder, easier...
若形容词音节是三个或三个以上就在前面加上more比较级，more beautiful, more difficult...
much是用来修饰形容词比较级的，加深程度，表示“...得多”
This problem is harder than that one.
这道题比那道题更难。
This problem is much harder than that one.
这道题比那道题难得多。
She is much more beautiful than her mother.
more beautiful是beautiful的比较级，much在前面修饰比较级
她比她妈妈要漂亮得多。

clean是个单音节词，比较级直接加er，cleaner就行，不需要more构成
而much cleaner可以，表示“干净得多”

多音节形容词和副词的比较级前面加MORE,别的单音节或双音节(非特殊情况)比较级加ER.MUCH加在比较级前加深程度.
比如,clean-cleaner-much cleaner
expensive-more expensive-much more expensive
much more后面可加可数名词复数或不可数名词
比如,much more apples
much more money

much more+adj.
more+adj. 当adj. 音节多时
adj.+er 当音节较短

cleaner后面还要加比较。。 much cleaner than before, much more cleaner than before都可以，much more 强调“更加”。

more clean;much cleaner