一， 完形填空（共10小题；每小题2分满分20分）
阅读下面短文，从短文后各题所给四个选项（A、B、C、D）中，选出可以填入空白处的最佳选项，并在答案卡上将该项涂黑。
The earth is our home. We must take care of it. Life today is easier than it was __1__ years ago, but it has brought some new problems. One of the biggest problems is pollution. We can see it, smell it, drink it and even hear it.
