There are a number of ways to help improve your memory, so you shouldn't____sad.

    My first way is that if you want to remember something, you have to review it____.You may want to go over the material two days after you have____it, then a week later, then two weeks later, and then a month later. After a month you will find that you can remember the material.

    My second____is to use a colored pen to highlight(用颜色标出) the important parts on your book. This will help you in two ways. First, it will help you focus on the____parts when you learn the knowledge. It is always____than remembering everything.____this will make reviewing better. When you open your book, the color parts will show you the most important things immediately.

    Another good time for remembering information is in the morning because you have just ____the whole night and your brain is fresh and clear. So it's easy to remember the important information in the morning.

    Winter is a really fun time of the year—it's great to have snowball fights and build snowmen. ____ When it's cold outside and you're not prepared, you can feel uncomfortable. Lucky for you, learning how to stay safe is not difficult.

    ____Wearing thick clothes is the best way to stay warm in the cold. Depending on where you live and how cold it is, some kids may need more clothes, some less.

    Take that hat. You maybe wear a large overcoat and ready to go, but are you forgetting something?____You'll stay much warmer with a hat than without one—tons of body heat escapes right from your head.

    Drink up. Sounds like advice for hot weather, not cold weather, right?____When you're outside in the cold and breathing hard, your body loses a lot of water through your breath. And the best way to get that water back is to drink up!

    Take it easy. Sometimes if you're out having fun, it's easy to forget to pay attention to your body. But if your body temperature drops even 4 or 5 degrees while you're outside, it can make you feel terrible.____And if you ever feel weak, those are signs that you have to take it easy indoors for a while.

A：倾倒稀盐酸____；

B：点燃酒精灯____；

C：给铜绿固体加热____；

D：加入铜绿粉末____．

当今世界经济发展的重要特征是（　　）