about 是介词,介词后面要加动名词doing,例如,for,in,at,of,之类的介词也是这样,thank you for helping me,be interested in reading,be good at playing basketball,be fond of swimming...
How about doing sth 是固定的句型.等于what about doing sth.都是对他人提建议时的用语。常用的还有why not……,why don't you……等 eg: How about getting her a scarf? What about getting her a scarf? why not get her a scarf? why don't get her a scarf?