Although James Cook the first westerner to have discovered Australia,New Zealand and Hawaii,his travels led to the creation of more accurate and reliable maps for vast parts of the world.
A. isn’t
B. wasn’t
C. must have been
D. may not have been
网友回答
A. isn’t
B. wasn’t
C. must have been
(答案→)D. may not have been
解析：从to have discovered及 led 可知此处表过去，从句意上看应为“过去可能不是”，故选D。