Mn giúp em với ạ, em cảm ơn mn ạ

44. Dr Joseph Bell was a professor at the medical school. Doyle studied at this school from 1876 to 1881. (where) 

Dr Joseph Bell was a professor at the medical school where  Doyle studied from 1876 to 1881

Where thay thế cho trạng ngữ chỉ nơi chốn

45. We didn't plan well for the trip. Many things went wrong. (if)

If we had planed well for the trip, many things wouldn't have gone wrong 

câu đk loại 3=> sự việc ko có thật trong quá khứ: If+ S+ had+ P2, S+ would have P2

46. Many people are unware of the negative effects of hazardous chemicals. They don't stop using them. 

If many people were aware of the negative effects of hazardous chemicals, they would stop using them. 

Câu đk loại 2=> sự việc ko có thật ở hiện tại: If+ S+ were+ N/adj, S+ would V