Question 22: If we ______________ the plans carefully, we would not ha

Question 22: If we ______________ the plans carefully, we would not have had so many serious mistakes

• A. study
• B. had studied
• C. studied
• D. were studying

Cấu trúc câu điều kiện loại 3: If + S + V(quá khứ hoàn thành), S + would/could/might + have + Vpp.