微课内容说明:Step1. 要求学生找出教材中含有现在完成时的句子Go over the news story, Boy missing, police puzzled, and find the sentences using the present perfect tense.学生将找到下面的句子.1. Police in America have stepped up their search for a fifteen-year-old boy who went missing 2. This incident has received great interest due to reports of 3. I havent seen Justin since.4. Its happened to me!5. When asked , who has taken charge of the case, told 6. So, while we have not dismissed the idea, we are looking into other possibilities as well.Step 2 现在完成时的定义 提供更多例句 Step 3 带领学生回归教材,这是全课的重点和难点。