环境地质学的理论体系包括（）。
A.基础理论
B.专业理论
C.系统理论
参考答案：A, B
.It is said that pandas ___________ in our country year after year.
A．are being disappeared
B．are disappearing
C．will be disappeared
D．will disappear
清晰易懂的演示结构的表达的结构越（）越好。
