听力原文： It was not until the Middle Ages that gardens once more became important in British life. Monasteries had both kitchen gardens and herb gardens to provide the practicalities of food and medicine. The monastery cloister provided an open green space surrounded by covered walks, generally with a well, or fountain at the centre. Castles sometimes made room for small courtyard gardens, with paths through raised flower beds. Other common features of medieval castle gardens include turf seats and high mounds, or mounts, which provided a view over the castle walls. As castles gave way to fortified manor houses in the later medieval period, the garden became a simple green space surrounded by hedges or fences. Games such as bowls or tennis took place on the lawn. The next stage of the English garden came after the Reformation. Many landowners enclosed common land to create parks for keeping deer or cattle. This "natural" landscape gave way to formal gardens near the house, still sheltered from the outside world by hedges or walls. The 18th century saw a swing from Renaissance formality to a more "natural" look. Lines were no longer straight, paths curve and wander, and parterres were replaced by grass. The garden became open, a park joining the house to the outside world rather than a carefully nurtured refuge from it.
What is this passage mainly about？

A. The history of the English gardens.
B. The English gardens in the Middle Ages.
C. The features of the current English gardens.
D. The passion of the English people for gardens.