优质解答
1.是否定句之后通常用 or代替 and.如：
He spoke loudly and clearly.他说话声间宏这且清晰.
He didn’t speak loudly or clearly.他说话声音不大且不清晰.
2.祈使句＋and =if,而祈使句＋or = unless.如：
Work hard,and you will succeed.(=If you work hard,you’ll succeed.) 努力工作,你就会成功.
Work hard,or you won’t succeed.(＝Unless you work hard,you won’t succeed.) 努力工作,否则你就不会成功(from www.zkenglish.com).
3.有时 and与 or可换,如：life and (或or) death (在死)；有时and no与or互换.如：
He has no brothers and no sisters = He has no brothers or sisters.他没有兄弟姐妹.
4.在选择疑问句中,用or 不用and.如：
Is it a pen or a pencil?那是钢笑还是铅笔?
Which is bigger,the sun or the earth?太阳和地球哪个大?
5.在both 之后用and,在either之后用or.如：
Both you and he are right.你和他都是对的.
Either you or he is right.不是你对就是他对.
1.是否定句之后通常用 or代替 and.如：
He spoke loudly and clearly.他说话声间宏这且清晰.
He didn’t speak loudly or clearly.他说话声音不大且不清晰.
2.祈使句＋and =if,而祈使句＋or = unless.如：
Work hard,and you will succeed.(=If you work hard,you’ll succeed.) 努力工作,你就会成功.
Work hard,or you won’t succeed.(＝Unless you work hard,you won’t succeed.) 努力工作,否则你就不会成功(from www.zkenglish.com).
3.有时 and与 or可换,如：life and (或or) death (在死)；有时and no与or互换.如：
He has no brothers and no sisters = He has no brothers or sisters.他没有兄弟姐妹.
4.在选择疑问句中,用or 不用and.如：
Is it a pen or a pencil?那是钢笑还是铅笔?
Which is bigger,the sun or the earth?太阳和地球哪个大?
5.在both 之后用and,在either之后用or.如：
Both you and he are right.你和他都是对的.
Either you or he is right.不是你对就是他对.