The weather is very cold today, so students should wear more clothes, take care of your health, don't catch a cold, so it has more energy to study.
It is very cold today. So, in case of getting cold, you had better put on more clothes and pay attention to your health. Thus, you can more focus on studying.
Today the weather is cold, so students must put on more clothes, pay attention to good health, don't have a cold, so that they will have more energy.