一般現(xiàn)在時(shí),第3人稱(chēng)單數(shù)要加如
He always(usually) does his homework after dinner.
He never throws rubbish about.
一般過(guò)去時(shí),即使有usually,always等,也不用加s,而是用過(guò)去式,如
He always(usually,never) did his work after dinner last year.
如果前面有情態(tài)動(dòng)詞,如can,will,would,may,can,could,should,might,must,need等,或是不定式（動(dòng)詞前加to）的,就不用加s
如
He can always do his homework by himself.
He will usually do his homework after dinner.
His teacher asks him to do his homework after dinner.
有時(shí)候,一個(gè)句子里有兩個(gè)人物,但動(dòng)詞還要加s,是因?yàn)橹髡Z(yǔ)只有一個(gè),如
He usually GOES to the park with his classmates.
句子中,classmates不是主語(yǔ),he是主語(yǔ),所以要加s(因?yàn)間o是特例,要加es)
常見(jiàn)的就這些