某高校“统计初步”课程的教师随机调查了选该课的一些学生情况，具体数据如下表:为了判断主修统计专业是否与性别有关系，根据表中的数据，得到K
一What should we do first if we want to develop our village? 一A lot of new roads __________．I think． A．must build B．have to build C．must be built
翻译下面文言文 颜渊喟然叹曰：“仰之弥高，钻之弥坚。瞻之在前，忽焉在后。夫子循循然善诱人，博我以文，约我以礼，欲罢不能。既竭吾才，如有
Instead of making progress, my work ______ seems to be going backwards. A. actually B. exactly C. hardly
— What did the teacher say just now? — Sorry, I didn’t hear it. I out of the window. A. look B. looked C. am looking
It is already home to whales, seals and polar bears, but soon the Arctic (北极) must find __1__ for some Chinese visitors. A team of nine scientists will __2__ to the Arctic this month to mark the o
下列物质中既有离子键，又有共价键的是 （ ）A.H2O B.CaCl2 C.KOH D.Cl2
正五棱柱中，不同在任何侧面且不同在任何底面的两顶点的连线称为它的对角线，那么一个正五棱柱对角线的条数共有（ ） A．20 B
为何值时，
有意义？
，利用单位圆中的三角函数线得