选词填空
run, bad, home, ride, thirty, doctor, strong |
Jack is very fat. He is worried about his health, so he goes to see his ____.
"You are 100 kilograms. It's very ____. You must lose about 20 kilograms." The doctor told him.
"Oh, what should I do, Doctor?"
"You should ____5 kilometers a day for a month."
Jack goes home and does these things.____days later, he calls the doctor.
"Doctor," he says, "I'm calling to tell you about my weight(重量). I'm 80 kilograms now. But I'm 150 kilometers away from ____. I don't know how to get back!
既是偶函数又是周期函数，若
，且当
时，
，则
的值为 