Giúp với ạ, từ câu 16 đến câu 10 bài 4

16. Coming into his room, he found that someone broke into it. 17. It always rains when they had just cleaned the windows. 18. The last time I saw him, he wore a black suit. 19. By the first of next July I had worked for this company for 20 years. 20. This is the talking between two fr ...