What would happen if you tried to blow a soap bubble in freezing weather? Would it freeze solid(固体) and fall to the ground? Would you have to hit it to break it? These questions happened to me on a cold winter day. It was too cold to play in the snow, but it was a perfect time to experiment with blowing frozen bubbles.
To blow frozen bubbles, I used dishwashing soap and a drop of glycerin（甘油） to make it even better. I chose a place out of the wind, and blew bubbles the same way I always do. I watched to see what would happen. Here’s what I learned.
If the temperature is low enough, the skin of the bubbles frosts over (结霜), becoming cloudy instead of clear. And what about those rainbow swirls（旋转） you see in soap bubbles? The rainbow colors stay even when the bubbles frost, but they don’t swirl anymore. The bubbles still stay in the air. They don’t fall to the ground any faster than they would on a warm summer day.
When these frozen bubbles break, they don’t turn into small water drops as summer bubbles do. They turn into flashing rainbow confetti（碎屑） and move slowly to the ground. Sometimes a frozen bubble will roll across the snow without breaking. If nothing disturbs the bubble, it may stay there for a long time. Sometimes I could catch a bubble and hold it until the heat of my hand made it pop.
I learned another thing about blowing frozen bubbles. It’s so interesting that I want to try it again next year.
It is the perfect time to blow frozen bubbles on a ___________day.

A．cold winter

B．warm spring

C．hot summer

D．sunny autumn

When the frozen bubbles break, _________.

A．they make a big sound	B．they turn into small drops
C．they fall to the ground like rain	D．they become rainbow confetti

The purpose of the passage is _______.

A．to learn how to do a science experiment

B．to show the experiment of blowing frozen bubbles

C．to discover games that are fun to play in the snow

D．to invent a new kind of soap that makes stronger bubbles