选C。 bigger than已经构成比较级。这里的much是强调副词，much bigger意为“大得多”。
选C
much
答案应选C,bigger是比较级，选项中能修饰形容词比较级的有C和D,但是more是用来修饰多音节形容词比较级的，例如：more interesting, more beautiful等等。故只能选much，且much常用来修饰形容词比较级，例如：much more interesting等等。
D
C much much修饰比较级
D 固定句型，more ... than ...
答：This room is twice bigger than that one. This room is three times as big as that...详情>>
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