21. exceptional=good=excellent=outstanding=brilliant=impressive=admirable超常的，例外的adj.
22. mating=courtship交配.
23. follow=track=tail=shadow=hound=stalk=stalker跟随，跟踪v.
24. good vision ability=vision is obviously more useful…好的视力
25. best=well=greatest=finest=ideal= top= number one
=ultimate=optimum=definitive=unsurpassed=record-breaking极好的adj.
26. surprised=amazed=astonished=astounded=be taken aback=startled感到惊讶的adj.
27. volunteer=subject实验研究对象n.
28. similar=resemble=like=alike相似的adj.
29. blind=can not see瞎的adj.
