一、有些动词只能接不定式做宾语
.例如：help,hope,ask,refuse,decide,promise,wish,pretend,expect,learn,plan,manage,agree,fail,offer,happen,seem等等.
二、有些动词或短语只接动名词做宾语：mind,finish,enjoy,suggest,consider,miss,keep(on),avoid避开,躲开,stand(忍受),allow ,practice