步骤四： 区别过去时和过去进行时 从概念上，结构上进行区别，并且做3道

Step four: the difference between past tense and past conduct <br>, from the concept of structural differences, and do three exercises to help understand <br>[design intent: to check whether students can distinguish two tenses. 】<br>Step 5: Distinguish between when and while <br>[design intent: the difference between when and while, for example, to compare the differences, and form a concept] to <br>complete Self check1 and 4a <br>[design intent: check whether the student masters the difference between when and while. 】

Step 4: Distinguish between past and past <br>Conceptually, structurally differentiate and do 3 exercises to help understand<br>Design intent: Check whether students can distinguish between the two tenses. 】<br>Step 5: Distinguish when and while <br>Design intent: the difference between when and while, the comparison of examples, and the formation of concepts<br>Complete Self check1 and 4a<br>Design intent: Check that students know the difference between when and while. 】

Step 4: distinguish past tense from past progressive tense<br>Conceptually, structurally, and do 3 exercises to help understand<br>Design intention: to check whether the students can distinguish the two tenses. ]<br>Step 5: distinguish when from while<br>[design intent: the difference between when and while, for example, to make a comparative difference and form a concept]<br>Complete self check1 and 4A<br>[design intent: check whether students master the difference between when and while. ]<br>