侵蚀基准面
参考答案：
河流侵蚀河床底部岩石，使河床降低的作用，侵蚀基准面是下蚀作用的极限。
---Could I borrow your book for one night?
---_______. I won't use it tonight.[ ]
A. By all means
B. Never mind
C. You are welcome
D. Of course, you could
下列哪种物质是磷酸化的抑制剂
A．阿霉素B．氰化物C．鱼藤酮D．寡霉素E．抗霉素A
