Jack feels terrible today. He has a cold. His throat hurts and he has a headache. He calls his doctor.
At the surgery, the doctor asks: "What is the problem?" Jack says: "I have a sore throat and I sneeze all the time. I also have a temperature."
The doctor checks Jack's chest and ears. "You can't go to work," she says. "You need to rest and drink a lot of water."
The doctor gives Jack a prescription. "Take this medicine three times a day," she says.
Jack goes home and goes to bed. Two days later, he feels much better. He can go to work again!