改错 31. She will phone her mother if she will have some difficulty. 32. When I came back, I saw a man to come in a big house. 33. I know the beautiful girl having on a red coat. 34. It ’ s too hot. Let us open the door, shall we? 35. The young man is an university student. 36. The old man with his students catch a big fish. 37. Why do some animals have two stomaches? 38. The room is enough big to live in for eight people. 39. The retiring man found another good job. 40. I told my son don ’ t play in a dangerous place.