单 元：Unit 1 Tales of the unexplained
板 块：Grammar and usage 2
Thoughts on the design:
Learn the differences between the present perfect tense and the present perfect continuous tense.
1. Learn how to form and use the present perfect tense.
2. Understand when the present perfect continuous tense is used in sentences.
Teaching procedures:
Step 1 Compare the two tenses
1. We use the present perfect tense to talk about an action completed in the recent pa st, and the present perfect continuous tense for an action that started in the past and is still happening.
现在完成时和现在完成进行时都表示动作从过去开始，但现在完成时可表示事件或动作刚结束，而现在完成进行时则强调动作仍在继续。
