英语介词分别在哪些句子后面加,像be interested in ,be covered by,为什么加in by

以一个短语be interested in 是表示对.感兴趣,是固定搭配,
后面的那个应该可以理解成是被动语态,即：被.覆盖.
For example:She is very interested in Shopping.
Himalaya is covered by snow the whole year.
希望对你有用.