3........?????????????

2. Other students were reading the article in book when i got to my desk
3. I look for book in the schoolbag when everybody had finished reading
4. Everybody has finished the article when i find book\
5. Teacher has explained someting when i finish article
6. I was looking for pen when teacher gives written exercise
7. I haven't finished when teacher was collecting work
8. I do the work when classmates had gone home