丝绸之路指历史上陆续形成的、遍及欧亚大陆甚至包括北非和东非在内的()线路的总称。
A、旅游
B、长途商业贸易
C、文化交流
D、运输
参考答案:B, C
With the development of the central and western China,more and more modem cities have
——in what was a wasteland ten years ago
A.built-up
B.sprung up
C.grown up
D.risen up
朱砂与磁石的功效应用有何异同?