路基地段CRTSⅠ型双块式无砟轨道，道床板宽度为2800mm，厚度为（）mm。
A.190
B.210
C.240
D.260
参考答案：D
Every year, _____ energy is spent on environment protection.
A．large quantities of
B．a good many
C．a great deal of
D．a plenty of
副皮质区
