The firemen know _____ to do.  

    Nowadays more and more Chinese teenagers find life more difficult without their parents. They don't know how ____housework. Because their parents do almost everything for them at home. This is a big problem.

    Joy is 14 years old. One day her parents____away on business(出差), so they asked Joy ____home alone. At first she thought she would be happy ____her parents were not in. She could do what she liked. But it was six o'clock ____the afternoon, she felt hungry.“Oh, it's time ____supper. Where can I get my food?”she said to herself.Later she found some food in the fridge, but she didn't know how to cook.At that moment, she missed her____very much. At last she could only go to the supermarket and____some food to eat.

    Many teenagers are the ____as Joy. So I think they should learn some basic life skills,____as cooking, cleaning their rooms or dressing themselves properly. They shouldn't depend too much on their parents.

乙酸和乙醇的酯化反应，可用如下过程表示：

即酯化反应实质是经过中间体再转化为酯和水，以上反应均为可逆反应，回答下列问题：

小红的爸爸从美国给小红寄回价值7.85美元的故事书，折合人民币多少元？（1美元折合人民币6.81元）

如图，直线ι是一次函数y=kx+b的图象，若点A（3，m）在直线ι上，则m的值是（   ）