1 . Instantly, we were busily preparing for the worst. The whole family had experienced such a storm before and everyone remembered the damage it had caused to stock and crops. There was very little we could do about the crops. But we needed to protect the animals in case the river flooded again. My older brother called his sheep-dog and began driving our small flock of sheep to higher ground above river. If the river flooded, they should be safe there.

2 . One explanation for this strong statistical pattern is that traveling requires time and energy, and people have limited resources for it. At the core is the effort that people are willing to invest collectively to travel to certain locations, trying to optimize their days.

3 . Saltwater crocodiles are the largest reptile in the world and can eat large prey (猎物). They hide at the edge of the water, waiting for prey. Then, without warning, they lunge. They grab their prey in their powerful jaws and drag it under water. Saltwater crocodiles don’t often miss their target.

One day, David George found himself in a swamp. It was the home of saltwater crocodiles. David knew they were there because he could see their tracks.

David thought his only chance of survival was to climb a tree and tie himself to a branch. Two big saltwater crocodiles, however, waited under the tree. He would have to come down sometime!

4 . I still have a thousand questions as to why I struggled to act. Why did it take me many circles around the mall and an argument with myself? I once wavered between helping her and ignoring her. All I know for sure is that while walking toward that woman at the bus stop, a miracle happened.