6. They said they were helping their students to do that project then
-> S said S V(lt)
7. My mother has decorated this tree since yesterday
-> S have/has VPII since…
8. The problem has been studied carefully by the scientists
-> S have/has been VPII by O.
9. This town, where I first met you, has changed dramatically 
-> where là trạng từ quan hệ thay thế từ chỉ nơi trốn
10. My boyfriend, who was injured in the accident, is now in the hospital
-> who là đại từ quan hệ thay thế từ chỉ người
11. Though the rain was heavy, they had a wonderful holiday
-> though : mặc dù, đi với mệnh đề
12. He has not come to see me for 5 years
-> S have/has not VPII for…
13. If I didn’t spend too much time looking at the smart phone’s screen, my eyes wouldn’t badly hurt 
-> Câu điều kiện loại II: If S V(QKD), S would(not) Vnt.
14. Our life has been affected terribly by Covid-19 pandemic
-> S have/has been VPII by O.
15. The boy said making his parents happy was his dream. 
-> S said S V(lt)