41. They are playing soccer at the moment
42. She often doesn't go shopping on weekend
43. They are not classmates
44. Is he your father?
45. Is she listening to music now?
46. Thanh and Hung are reading a wonderful story at the moment
47. Mai and Hang aren't playing the game at the moment
48. I often wash my clothes
49. She isn't at home now
50. Do you often write to your friend?