单项选择题 Of the following sound combinations, only _______ is permissible according to the sequential rules in English.（ ）

未知题型 1851年第一次国际博览会主建筑被称为 ，是世界上第一座用金属和玻璃建造起来的大型建筑。

单项选择题 Which of the following property of language enables language users to overcome the barriers caused by time and place, due to this feature of language, speakers of a language are free to talk about any