Grandfather was away from home on a business trip for a few days. Feeling a bit down, Bi Bi watched the movie "Fruit Robot." Every night, she watched it until 10 o'clock. Tonight was no different. From downstairs, Grandma called out:

Bi Bi, what are you doing?

I'm finishing watching "Fruit Robot!"

Okay, it's time to go to sleep.

Bi Bi acknowledged but because the movie was so captivating, she ended up watching past 10 pm without falling asleep. She said:

It's getting late; I should go to sleep now, Grandma.

So, Bi Bi went to sleep alongside her grandmother. Just as the bed started to feel cozy, Bi Bi heard her Grandpa's voice as he returned home. Excitedly, Bi Bi exclaimed:

Grandpa is back! Grandpa, could you please tell me a bedtime story?

Just give me a moment to change and freshen up; then I'll come and tell you a story before bedtime.

After Grandpa finished telling Bi Bi the story, he noticed that she was still fidgeting and reluctant to sleep.

Bi Bi, you seem restless. What's wrong?

Grandpa, my back itches a little, and I can't fall asleep... Can you scratch my back, please?

He gently scratched Bi Bi's back. After a while, when she started to snore lightly, he heard another cough, which made him realize that she had woken up.

Are you still awake?

Could you sing me the song "The Stork Comes Out to Eat at Night"? Why does the stork come out to eat at night?

After a lengthy search, Bi Bi eventually fell asleep.

The following day was no different. When she went to bed, Bi Bi continued to toss and turn, asking for a lullaby to help her fall asleep. That's when Grandpa told her:

I think the problem is that you're overworking yourself, which makes it hard for you to sleep.

You're probably right. I've been watching "Fruit Robot" too late for several days, and it's affecting my sleep.

Your biological clock is out of sync, Bi Bi.

What's a biological clock?

It's a natural rhythm in human behavior, such as eating and sleeping at regular times.

Bi Bi became concerned:

Grandpa, does that mean my biological clock is broken? Huhuhu. Grandpa, can you help me fix it?

Seeing that he hadn't answered, Bi Bi urged him again:

If you can't fix it, could you at least buy me a new one?

You can't buy a biological clock, my dear; it can only be reset. Even outsiders can't fix it; you have to do it yourself.

I don't know how to reset a clock!

It's not like fixing a machine; it's about developing good habits. You have to remember what I said: don't do anything after 9:30 p.m., and your biological clock will reset.

Listening to him, Bi Bi began to manage her time more effectively, going to bed at 9:30 p.m. every night. However, it was odd; she couldn't fall asleep once in bed. She started fidgeting again. He gently reminded her:

Remember, you have to reset your biological clock on your own. Lie still, close your eyes, and go to sleep!

Bi Bi tried her best to remain still, close her eyes, and fall asleep, but it was nearly 10 pm.

The following morning, Grandpa woke up Bi Bi. She was still lying in bed, only slightly stirring.

You're not going to school today, Bi Bi?

No, Grandpa. I have the day off. Please let me rest a little longer, and I'll get up at 10 o'clock for breakfast.

Why are you getting up so late? Your biological clock is still off.

At night, after finishing the bedtime story, the clock read 9:15. Bi Bi went to bed but still fidgeted and couldn't sleep. He placed his hand on her forehead and said:

Let's work on resetting your biological clock. Just close your eyes and remain still.

It took him four days to help Bi Bi overcome her biological clock problem. By Thursday night, Bi Bi was going to bed on time, waking up early in the morning, having breakfast, and going to school.