“You’ll think twice about plucking your eyebrows (拔眉毛) 16. ______ you find their important role,” says Greg Foot. They are one of 17. _______ most expressive(有表现力的) parts of our bodies. 18. ______ your eyebrows, you can tell your feelings to other people. 19._______ is that their only purpose (目的)? Over several thousand 20. _______ (year), we have lost lots of body hair, so it’s strange that hair still 21. _______ (remain) on our brows. Some scientists say that eyebrows mainly work as 22. ______ special form of protection for the eyes. In fact, their job is so 23._______ (importance) that some researchers are sure that if we didn’t have 24. ______ (they), we’d have evolved (进化) some other facial features to 25. ________ (do) the same task.

　　参考答案：

　　16. when 17. the 18. With 19. But 20. Years 21. remains 22. a 23. important 24. them 25. Do