Question

反义疑问句 Everybody can do it,__

Answer 1

答：can't they? 或can't he?
析：反意疑问句前肯后否，所以用can't, 只能用一个人称代词，不能用he or she, 习惯上用he指代每一个人（和汉语一样），不用she, 这引起女权主义者的反对，故借用中性的they 来代替he or she.
《Longman》词典上everybody同条目下有一个usage:
Anybody, every, and everybody are followed by a singular verb. They are sometimes followed by a plural pronoun A. (非正式) to avoid saying he or she, since there is no one word for this in English. (为避免用he or she, his or her )
eg. Everybody started waving their flags (正式用 his or her flag).
Everybody can do it if they try( 正式用 if he or she tries)
B. 在疑问尾句中如：Everybody has arrived, haven't they?
例一中，请注意flag的数，用了their, 用复数，而用了his or her则用flag 而hair在这里作不可数名词，不存在这个问题。所以原句中，如有his or her, 则选它（比较正式），男女都没意见，或选their.（大家都认可）

http://zhidao.baidu.com/question/235680266.html

Answer 2

Everybody can do it， can't they？

前肯后否

Answer 3

Everybody can do it ，can't they？

反义疑问句 前肯后否