A有些动词只是及物动词;它们不可以单独用,后面必须跟宾语.

　　False:Theyalwayswantafterlunch.

　　Right:Theyalwayswantacupofteaafterlunch.

　　False:Heissendingnow.

　　Right:Heissendingaletternow.

　　B有些动词只是不及物动词；它们可以单独用,如果后面想接宾语,动词后面必须加上介词.

　　Right:Heislookingaround.

　　False:Heislookingme.

　　Right:Heislookingatme.

　　Right:Heislisteningcarefully.

　　False:Heislisteningtheteachercarefully.

　　Right:Heislisteningtotheteachercarefully.

　　C有些动词既是及物动词,又是不及物动词;但是有时候词义会改变.

　　Thecustomerisaskingloudly.

　　Thecustomerisaskingforyounow.

　　Thecustomerisaskingaquestionnow.

　　Ifyouworkhard,youwillsucceed.

　　Ifyouworkhard,youwillsucceedinpassingtheexam(samemeaning).

　　Ifyouworkhard,youwillsucceedJohnasthemanagerofthiscompany(differentmeaning).