锐角A满足cosA=$\frac{1}{2}$，利用计算器求∠A时，依次按键 ，则计算器上显示的结果是____ ．

当遇到老师的不公平对待时，作为学生，应该（    ）

①有意疏远老师，避免再次发生误会     ②选择恰当的机会，主动解释清楚

③铭记在心，借机批驳老师                  ④学会从老师的角度想一想

在当代，随着科技迅猛发展，经济全球化步伐加快，各国都努力扬长避短，积极参与国际分工，不断加强国际合作，以达到更快、更好地发展自己的目的。这说明 (   )

阅读理解

      Peru(秘鲁)is the fifth largest Latin American country with a people of 14, 430, 000. Almost half of these people live in the city areas(地区). Around Lima, there were 20% of the total (总数) population in 1961. The population here grew faster than anywhere else and in another 35 years reached 1/3 of the total population.

      About 45% of the people are Indians and 50% are white or mixed（混合人种）and the others are Asians, Negroes(黑人)or people from other countries.

      In island areas, only about half of the people can read and write, but at the places near the sea, 2/3 of the people can read and write.