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
未知题型 通过这门课程的学习，你都有哪些收获？你认为，这门课程还需要在哪些方面进行改进？
未知题型 列车越过对位标停车时，司机应立即RMR后退对标，站台作业完毕动车后再报行调（）
单项选择题 Pitch variation is known as __________ when its patterns are imposed on sentences.
