向100g20%的氯化钠溶液中加入100g水,稀释后溶液中溶质的质量分数是[ ]

题型:选择题

问题:

向100g20%的氯化钠溶液中加入100g水,稀释后溶液中溶质的质量分数是[ ]

A.2.5%

B.5%

C.10%

D.20%

考点:关于溶液的计算
题型:选择题

Social skills are important in daily life .You shouldn’t a___小题1:____    talking to someone you recognize .People like a man who can talk     小题2:  (自信地) to every guest at a party . And you won’t make more friends if you    小题3:  (缺乏) the c  小题4:   to talk to people you don’t know . So you must learn small talk .

Before having a conversation , you’d better do a little a____小题5:___ planning. Having some low-risk conversation openers ready . For example ,think of a recent news story---not too serious. That way, you don’t damage your confidence . And always remember , communication i   小题6:   speaking and listening , because you won’t i   小题7:    people if you talk too much . You should show people that you are listening by your reaction such as keeping good eye     小题8:   (接触). Don’t    小题9:  (把目光从……移开) the person who’s talking to you .Don’t change the subject if you go to a ___小题10:     (社交场合) in another country , remember that social rules can be different .

题型:选择题
以下说法正确的是(   )
A.每个内角都是120°的六边形一定是正六边形
B.正n边形有n条对称轴
C.正n边形的每一个外角度数等于它的中心角度数
D.正多边形一定既是轴对称图形,又是中心对称图形
题型:选择题

影响爆破效果的三要素是什么?为什么说这三要素中岩体性质,特别是岩体结构面的影响最大?

题型:选择题

招标工作的内容有哪些?

题型:选择题

一般中型以上的公路水运工程施工单位,应当()组织一次安全检查。

A.每一个季度

B.每一个月

C.每一年度

D.每一星期

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