题目

下图是几种盐的溶解度曲线，下列说法正确的是(    ) A.40 ℃时，将35 g食盐溶于100 g水中降温至0 ℃时，可析出氯化钠晶体B.20 ℃时，硝酸钾饱和溶液的质量分数为31.6 %C.60 ℃时，200 g水中溶解硫酸铜达饱和，当降温至30 ℃时，可析出30 g硫酸铜晶体D.30 ℃时，将35 g硝酸钾和35 g食盐同时溶于100 g水中，蒸发时，先析出氯化钠Do you have to carry a heavy bag to school? Does it make your back (背部) hurt? Well, students at a high school in Kansas (堪萨斯州), America, have a meeting with their city’s mayor（/meM/市长） to complain (抱怨) about their heavy bags. They say their bags are giving them headaches, and making their necks (脖子) and backs hurt. The mayor says he is very sorry. He says students may do more of their homework on the Internet (国际互联网) to give their back a rest.1.A heavy bag may make students ＿＿.A. headache B. earache C. toothache D. A, B and C2. Kansas is in ____ .A. China B. America C. Australia D. Canada3.The students talk about their heavy bags to＿＿.A. the mayor B. their parents C. their teachers D. their friends4.The Mayor isn’t friendly, is he?A. Yes, he isn’t B.I don’t know C.Yes, he is D.No, he is5.The mayor says＿＿.A. he has a headache B. he wants the students to do more homeworkC. he is sorry D. he has to work hard