EXERCISE 3I. CHỌN TỪ/ CỤM TỪ THÍCH HỢP (ỨNG VỚI A, B, C, D) ĐỂ HÒAN TH...

16. The X-ray____________ in 1895.A. is said to have been discovered B. is said to be discoveredC. said to have been discovered D. said to discover