一篇英语作文，初中水平

多少字？没说我可写了。
Last Sunday,I went to a supermarket to buy some food to eat.Suddenly,I saw a thief thieving a lady's bike.So I ran into the supermarket and told the assistant that there was thief thieving a bike,and asked her for some help.Then she agreed me to use the phone to call “110”.Unluckily ,our conversation was heard by the thief.The thief put down the bike and ran away.