21. My cousin has a        grasp of what he has learnt, which makes him stand out in every

exam.

A. confidential       B. conservative       C. comprehensive       D. compulsory

22. It turns out that        we have done a good job of protecting the turtles for the weeks they

spend on land, we have neglected the years they spend in the ocean.

A. while       B. as       C. until       D. unless