下表列出了几种物质中的声速．请你至少写出两条信息：

几种物质中的声速（m/s）

①  ____；

②  ____．

短文改错。

Dear Jim,

    I'd like to tell you something more about our school sports meet. It was holding on Oct. 6th, it was a fine day. There were over 1,000 students and teachers attended it. Wang Lin, a student from my class won the 100-meters race. He finished the race in 12.6 seconds and broke the school record. The sports meet was really success. That was because we were all trying to do my best. Although I was not one of the winner, I was proud of that we had done.

    Looking forward to receive your letter.

Yours,

 Li Ping

下列现象中，不能用光在均匀介质中传播的原理来解释的是（ ）

实验室用取大理石12.5g，加入盛有100g稀盐酸的烧杯中，两者恰好完全反应（假设其他杂质不与盐酸反应，也不溶解）。烧杯内物质的质量变为108.1g。试计算:

①能制取二氧化碳多少g ?

②大理石中碳酸钙的质量分数？