Combine each pair of sentences into one, using a suitable Relative Pronoun
38. The boy is a friend of mine. You are using his dictionary.
39. The people were nice. We visited their house yesterday.
40. I like the house. Its walls were made of glass.
41. The woman is my sweetheart. I understand her the best.
42. The friends went to Canada. I worked with them last year.
43. The things are strange to me. He is talking about them.
44. Vietnam is the country. I was born there.
45. New York is the city. He visited it when he was in America last year.
46. We visited the factory. Many modern cars were painted in that factory.
47. December is a month. It is the coldest in the USA in this month.