What were you doing when you____ ( hear) the news?
总体由编号为01,02,…,19,20的20个个体组成.利用下面的随机数表选取6个个体,选取方法是从随机数表第1行的第5列和第6列数字开始由左到右依次选取两个数字,则选出来的第6个个体的编号为( )
根据图写出各个结构名称。
1____ 2____ 3____ 4____ 5____
6____ 7____ 8____ 9____ 10____
A:Look! This is the flag of ____. Do you know?
B:Yes, I ____ about it. It has five yellow stars.
A:What is the capital ____ of China?
B:It's Beijing. Tian'anmen Square is in Beijing. It's ____ .
A:What do you ____ ?
B:Chinese.
A:Great!
试验次序
第1次
第2次
第3次
第4次
所取样品的质量/g
25.0
加入稀盐酸的质量/g
50.0
100.0
150.0
200.0
反应后烧杯中物质的总质量/g
72.5
120.0
167.5
216.2
请回答下列问题并计算: