连词成句。

读某地等高线示意图，回答问题．

某物理兴趣小组的同学，用煤炉给10kg的水加热，同时他们绘制了如图所示的加热过程中水温随时间变化的图线．若在6min内完全燃烧了2kg的煤，水的比热容为4.2×10³J/（kg•℃），煤的热值约为3×10⁷J/kg．求：

（1）煤完全燃烧产生的热量；
（2）经过6min时间加热，水所吸收的热量；
（3）煤炉烧水时的热效率．

    Hi! My name is Ben. I'm 12 years old. I'm very helpful. I usually wash clothes and clean the rooms at home. I always help my teachers at school. And I am a foodie(吃货)，I like ice creams. They are sweet. And potatoes are my favourite vegetables. I like fruits, but I don't like bananas.

    I'm a cool boy，too. I like playing ping-pong，football and I can swim very well. I was afraid of dogs before，but now I have a pet dog. It drinks orange juice every day. It can play with a ball, it's so cute. I like it very much.

    What am I going to be? Mm…I want to be a police officer. Because helping people is fun for me. I will study hard and do more exercise.