单项选择题Leacock can be described as all of the following EXCEPT ______.
单项选择题The book on the fictional town of Mariposa presumably ______.
单项选择题Which of the following is TRUE
单项选择题What distinguishes the end-Permian mass extinction from other similar devastations
单项选择题The study of the end-Permian mass extinction is hindered by all of the following EXCEPT ______.