根据汉语提示完成句子。
1. 城里的人们有时会去乡下享受自然风景。
People in the city sometimes go to the countryside _____ _____ _____.
2. 现在人们会通过发送电子邮件来彼此交流。
Nowadays people send e-mail _____ _____ _____ each other.
3. 在美国人们通过握手来表示问候。
In the United States, people _____ _____ _____ _____ their greetings.
4. 那个老太太看着孩子们过马路。
The old lady looked at the children _____ _____ the street.
5. 昨天我花了很长时间算出这些难题。
It took me much time _____ _____ _____ these problems yesterday.