•England was once a densely wooded country (= a lot of trees grew close together there).英格兰曾经林木茂密。

•Mexico City is one of the most densely populated cities in the world (= a lot of people live close together there).墨西哥城是世界上人口密度最大的城市之一。

•His books tend to be rather densely written (= contain a lot of information and ideas and are difficult to understand).他的书往往内容庞杂、晦涩难懂。