26. This is the house that Jack ______ three years ago. A. was building B. builds C. had built D. built 27. He ___________ the effects of radiation

26. This is the house that Jack ______ three years ago. A. was building B. builds C. had built D. built 27. He ___________ the effects of radiation when he suddenly died A. was studying B. studied C. had been studying D. has studied 28. The train ______ when I ______ at the station. A. … Đọc tiếp