哪些介词后面必须跟不定式做介宾?答:1.加原形:情态动词和助动词等,如:can,could,may,should,might,must,ought,need,have,let,make,help sb+do sth.2.加不定式 want,would like,like,love,be going to,go on,hate,begin,continue,start,ask,tell,afford,agree,aim,appear,arrange,believe, care,choose,claim,come,consent,dare,...