Either the boy or his sister must have eaten___dinnerher his their哪个啊 为什么

Either the boy or his sister must have eaten___dinnerher his their哪个啊 为什么 Either one or the other hi,boy!see you the National Day! Either one or the other的意思 the boy is too short to reach __ the book __the dictionary on the shelfa) both andb) neither norc) either or either...or... the boy is too short to reach _ the book _the dictionary. 请问这里应该用either or 还是both and呢.?为什么另一个不对呢?谢谢! EITHER OR 和EITHER NOR! the boy can find his way home变成否定句英文the boy 什么hi -------the boy have -------brothers or sistres Either you or your father( )TV in the evening. They either exactly the same word or very similar .翻译 either one or the other中文意思快 Either you tell the truth~or you say nothing、是什么意思 Either the file is damaged or was notcorrectly installed. 补充：＿＿the boy ＿＿the girl are doing their best to finish the work on time. A.Either ;or B.Neither ;nor C.Not only ;but also D.Both ;and Hi boy!you are Can students either travel or work during the vacation?不是说either要放在句末么?