A.Why it is difficult to use aerial photographs in research. B.Why oceanic research is so limited. C.How oceanic research has helped land research, D.How fossil remains are obtained from deep sea.
A.Why B. B.Why C. C.How D.How E.
【参考答案】
B B【解题思路】四个选项差别较大，但有两项提及了0ceanicresearch，听音时可重点辨别。【解析】短文......