单项选择题
A.you don't know how to express your gratitude. B.You don't know how to greet other people. C.You suddenly forget what a word means. D.You don't understand why a foreigner shrugs.
A.is an occupational disease of foreign people B.may lead to very serious symptoms C.is actually not a disease D.is incurable
A.They thought highly of it and accepted it at once. B.They just accepted it at once without any hesitation. C.They just thought it a joke. D.They thought it was too artificial and took a long time to accept.