因為以前散步的人很多，自然也不會在意，人少了後偶爾就會注意一些戴著口罩

因為以前散步的人很多，自然也不會在意，人少了後偶爾就會注意一些戴著口罩來散步的人

結果 (英文) 1:

Because there were a lot of people walking in the past, naturally, I would not care about it. When there were fewer people, I would occasionally pay attention to some people who wore masks for walking

結果 (英文) 2:

Because there were many people walking before, they would not care. When there were fewer people, they would pay attention to some people who came for a walk with masks

結果 (英文) 3:

Because there used to be a lot of people walking, naturally will not care, less people will occasionally pay attention to some wearing masks to walk people