Here are complete sentences based on the prompts:

41. My mum is taking a train to the city centre at the moment.

42. They would like to swim in the lake.

43. Tom and Peter are riding bikes to the countryside now.

44. He is going to stay in the city for three days.

For the questions:

45. What should tourists visit in this city?

46. What does William suggest trying in the village?

47. Why do you love living in the countryside?

For the rewritten sentences:

48. There are many famous tourist attractions in Quảng Ninh Province.

49. My father avoids using his smartphone at bedtime.

50. Tourists love traveling to the countryside because they enjoy the clean air.