Here are the sentences based on the provided phrases:

46. In city life, there are a lot of shops, shopping centres, and supermarkets where we can buy anything we need, making daily errands convenient.

47. The nightlife in cities is very exciting, offering many amenities and activities that keep the social scene vibrant and enjoyable.

48. However, pollution is one of the biggest problems in cities because of the large number of private cars, which negatively impacts air quality and health.

49. Traffic jams often happen during rush hours, leading to road accidents, which is a serious concern for commuters in urban areas.

50. Living in the city has both advantages and disadvantages; ultimately, it is your own decision whether to live in the city or not, depending on your lifestyle preferences.