请您设计一个实际生活情境来表示分式方程24x-241.2x=20的意义，并解答这

大黄止血的有效成分是

A．大黄素
B．番泻苷
C．大黄鞣质
D．大黄酸
E．芦荟大黄素

信用能力指数这一指标是由亚历山大·沃尔在20世纪初提出的一个概念。（）

情景交际运用

IX. 根据短文内容，选择填入恰当的词语。（每空一词，每词1分，共6分）

Linda and Jenny are senior 3 students in our school. They are from Hong Kong. It is a busy city, and sometimes it is very 小题1: n______ because of so many tourists. Different from that, Xiamen is more 小题2:p           . Linda is a quiet girl so she likes to study here very much. But her sister Jenny 小题3: p        Hong Kong because she loves shopping.

After 小题4: g             next year, Linda will go to London for further education, and Jenny is going back to Hong Kong. Linda learns from a travel book that the 小题5:w_________ there is rainy. She needs to prepare an umbrella and a raincoat. Jenny thinks that she will be really小题6:c___________ when she comes back to Hong Kong.

pm2.5比pm10颗粒径小，富含大量的有毒、有害物质且在大气中的停留时间长、输送距离远，对人体健康和大气环境质量的影响更大，这种说法正确吗？（）

A.对

B.错

下面关于理想的焊接合金必须具备的性能的表述中错误的是（）

A.焊接合金的成分，强度，色泽等应尽量与被焊接的合金接近

B.焊接合金熔化后流动性大，扩散性高，能均匀的达到焊接界面，且与被焊接的合金牢固结合

C.焊接合金在加热和应用过程中应有良好的抗腐蚀和抗玷污性

D.焊接合金的熔点应该与被焊接的合金接近或相等