Riddles 谜语猜一猜

1. Im tall when Im young and Im short when Im old. What am I?

Hint：You may need it when you are having your birthday party.

2. How many months have 28 days?

Hint：Every month in a year has 28 days.

3. What goes up when rain comes down？

Hint：You will use it when it rains.

4. They come out at night without being called，and are lost（消失的） in the day without being stolen（偷竊）. What are they?

Hint：They are in the sky.