光缆的组成包括：（）。
A.光纤
B.缓冲管
C.加固
D.外套
参考答案：A, B, C, D
——Why are the housing prices in big cities going up all the time?
————One reason is that people are__________ into overcrowded cities in great numbers.
A．breaking
B．filling
C．pouring
D．hurrying
限制型心肌病噬酸性粒细胞增多
