giải thích hộ vs ạ 12. John F.Kennedy wouldn’t have died in 1963 if he _________to Dallas. A. didn’t go B. wouldn’t go C. hadn’t gone D. not go 13. One of the students in my class _________off sick today. A. were B. was C. have been D. are 14. Alan and Ruth took these photographs_________. A. themselves B. herself C. himself D. ourselves 15. The teacher said that we had to learn all these expressions_________heart. A. on B. with C. by D. in 16. He was homesick, and he_________all his family and friends. A. lacked B. missed C. desired D. hoped