Besides后面接动词是用不定式还是用动名词?老师说表示“除了”的介词but, except, besides后面接动词时,要用不定式(有时有to,有时不用to),不用动名词。但是,我看到了下面一句:
Mary often helps me with my lessons besides completing her own.
为什么这句在besides 后用动名词completing?
besides后面接动词的用法:如果句中不含动词 do 或不定式 to do , 那么后面习惯上用v - ing 形式。例如:
He often helps others with their studies besides completing his own. 他除了完成自己的学习任务外,还经常帮助别人学习。
如果含有实义动词 do, besides 后也可接 v- ing 形式 ,但不如接不带to 的动词不定式更普通 。例如:
What has he done besides writing the paper? (=What has he done besides write the paper?) 除了写论文,他还做了什么?
(《薄冰英语惯用法词典》p. 114-115)