Saturday morning, I time my homework.

I can my time the book.

It was cold that he go out.

Mike is speaking in front of others.

Jane started TV after her homework.

The next morning, my sister and I a terrible surprise. When we looked out of our tent, we saw a big snake near the fire. I was so that I couldn't move. We shouted to our parents to let them know about the . My dad started to jump up and down in their tent. This the snake and it moved into the forest near the lake. My dad told me later that snakes don't have but can feel things moving. He also told me it was not to go near a snake. This was a very lesson for me.

Why do we yawn(打哈欠)? Well, scientists are not really sure. Some think we yawn because we feel bored. Others believe yawning has something to do with breathing(呼吸). When there is too much carbon dioxide(二氧化碳) in our bodies, our bodies will tell the brains(大脑) to breathe deeply. That causes a big yawn. In 2007, scientists said people yawned to cool down(使冷静下来) their brains. These scientists found people yawned more often if they were warmer than others.

Scientists are trying to find out why yawning happens and why it is so contagious(可传染的). But they are only sure that when one person yawns, everyone else nearby wants to yawn, too.