单选题
Dolphins are sleek and powerful swimmers that found in all seas and unlike porpoises have well defined, beaklike snouts and conical teeth.
【正确答案】
B
【答案解析】答案：B
分析：应该是被动式。
改正：that found à found/that are found
翻译参考：海豚是圆滑有力的水手，在所有的海域里都存在。和porpoises不同,它们有着轮廓分明的像鸟一样的嘴和圆锥形的牙齿。