甲、乙、丙三名射击运动员在某次测试中各射击20次，三人的测试成绩如下表
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分别表示甲、乙、丙三名运动员的这次测试成绩的平均数，则的大小关系是 ；
分别表示甲、乙、丙三名运动员的这次测试成绩的标准差，则的大小关系是 ．
Parents always try to /prə'vaɪd/ a good environment at home for their children．
Li Lei is an h boy，he never tells lies．
My favorite month is S ，because we have Teachers' Day in this month．
Eric， your car is so dirty． You should go and get it （wash）．
When he heard the good news， he couldn't help （jump）．