阅读下面的短文，在空白处填入一个适当的词，或填入括号中所给词的适当形式。

I was(bear) in a small city. The cityvery(different) when I was young. There were some tall(building) like churches, but there weren't any tall office buildings. Therefewer cars and more bikes. There weren't any problems with traffic, and thereany pollution (污染). The air was clean. Thereso many people then. There(be) more space for everyone! Therelots ofchildren in the city. Many of themmy friends. We should protect (保护) our environment (环境).