【多选题】重点调查只需在调查对象中选择一部分重点单位进行调查。这是因为
A.
重点单位虽然项目不多,但对所调查的标志而言,它们在总体中占有很大的比重
B.
当所调查的标志改变时,重点单位一般也随之改变
C.
通过重点调查,主要是为了掌握调查对象的基本情况
D.
在一定意义上,重点调查也可以起到推算总体指标数值的作用
【单选题】No investment offers a better return than giving the children the best start in life. Research has shown that for every US $1 spent -I would say invested -- on early childhood programs, countries enjo...
A.
It plays an essential role in fighting against poverty constantly.
B.
Countries will save later costs by seven times the amount once invested.
C.
Young children who receive good early care will thrive physically and mentally.
D.
Research has invested US $1 for each child and the countries have enjoyed the benefits.
【单选题】0 3 D30 35 在总体单位中不进行任何有目的的选择,而是按随机原则,纯粹偶然的方法抽取样本的技术是 ( ) 。
【判断题】城市绿地系统是城市生态系统中具有自净能力的组成部分之一,起到主要的引导作用。
【判断题】慢性鼻炎分为慢性单纯性鼻炎和慢性肥厚性鼻炎。
【判断题】城市绿地系统是城市生态系统中具有自净能力的组成部分之一,起到主要的引导作用。
【单选题】The passage tells us that in the future ______.
A.
children will not be taught in schools
B.
no teachers will be needed
C.
teachers will be much more knowledgeable
D.
children will learn life skills at school
【单选题】关于运算符重载,下列说法正确的是( )。
C.
流插入运算符可以重载成类的成员函数,也可以重载成类的友元函数