Ⅰ.单词拼写
1．His lectures ranged over a ________(多样)of topics.
2．The crime rate is a ________(征兆)of social unrest.
3．Do keep the ________(毒药)away from your children.
4．The police play a ________(至关重要的)role in our society.
5．It is necessary to build first ________(帮助)centers in the coal mine.
