英語(yǔ)句子表達(dá),既要注意主謂一致,又要兼顧時(shí)態(tài).因此,你給的句子要修改成：
We ask people【 who did not come here the reason】 why 【they did】 not come.
We ask everyone【 who did not come here】 the reason why【 they did 】not come.
說(shuō)明：they后面一般現(xiàn)在時(shí)態(tài),都是用【復(fù)數(shù)形式】.
集體名詞單復(fù)數(shù)情況變化分類：
1、只當(dāng)作復(fù)數(shù)看待的名詞,謂語(yǔ)動(dòng)詞自然使用復(fù)數(shù)：
people(人)（做“民族”時(shí),復(fù)數(shù)形式是peoples）,police,cattle,staff 等.
2、單復(fù)數(shù)形式取決于單詞表達(dá)意義的常見(jiàn)詞：
class,group,team,family,government等,當(dāng)表示組織單位時(shí),當(dāng)作單數(shù)看待；表示組織單位中的成員時(shí),當(dāng)作復(fù)數(shù)看待.例如：
His family is large.
The family are watching TV.
3、everyone,everybody等不定代詞,在上下文使用人稱代詞指代時(shí),為了使用方變,經(jīng)常使用they,代替his or her.例如：
We ask everyone if they have their own learning methods.
祝你開(kāi)心如意!