cos(-50°)=k,则tan130°=_________(用k表示)。
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编码组成蛋白质的20种氨基酸的密码子数是()。
A.16
B.20
C.61
D.64
E.60
I was ____ to see the lack of fairness of the football match.[ ]
A. surprising
B. shock
C. affected
D. moved