二． 练习
１． 填词
１） Traffic creates a great deal of p_________ in many big cities.
２） There was a c_________ of over 1,000 people in the street.
３） It’s a big i__________ city where they make cars and electronic equipment.
４） Be careful! It’s d__________ to walk around town late at night.
５） It’s a very a__________ town with a lot of beautiful buildings.
６） In some countries, it is __________(不安全) to drink the water because it is dirty.
