单句指错，求大神解答，请说明怎么改

单句指错，求大神解答，请说明怎么改
26. The factory which I have worked for a long time is near my house
A B C D
27. We walked as fast as we could, hoped to catch the 9:30 train
A B C D
28. Liu Xiang is a great runner. He won his first gold medal on the age of 19
A B C D
29. The train that he was looking forward to arrive a few minutes ago
A B C D
30. I live in a room who’s windows open to the south.
A B C D