题目

阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空。(每空不多于3个单词) The Internet is veryimportant in our life. But do you know about (it) history? The Internet can't work computers.Enid invented(发明) the (one) computer in 1946. But it waslarge and heavy. It was as large asroom.In the 1960s, (scientist)started to study the Internet. At that time, only the army could use it(save), send and receive information. Inthe 1970s, the Internet came into offices, bank, hospita下列有关0.2mol·L-1BaCl2溶液的说法不正确的是 [     ]A. 500mL溶液中Cl-离子浓度为0.2 mol·L-1 B. 500mL溶液中Ba2+离子浓度为0.2 mol·L-1 C. 500mL溶液中Cl-离子总数为0.2NA D. 500mL溶液中Ba2+和Cl-离子总数为0.3NA