than作副词,是修饰动词的,一般放在动词后面,或用于比较级.

than作介词用,后加doing.（than doing sth.）并不是前面的动词用什么形式,后面的就用什么形式,只是后面只能用doing.

注意：rather than后用动词原形：prefer to do rather than do 宁愿.而不
=would do rather than do
=would rather do than do

望采纳!祝开心!