完成反意疑问句。

1. The Morse Code is rarely used today, _____________?

2. He made few mistakes in the test, ____________?

3. Nothing is more important than learning, ____________?

4. He could hardly remember me, ____________?

5. There is a little milk in the bottle, _____________?

下图是某区域等高（深）线示意图。读图回答下面各小题。

近几十年来这种凸向越来越大，对此应采取的根本措施是（）

A.禁止滥采滥挖珊瑚礁

B.经常使用挖泥船清除泥沙

C.做好流域内的水土保持工作

D.禁止滥采滥挖海沙