A：這兩個動詞片語雖都意為「充滿，裝滿」，但含意並不相同，所以不能互換。
Full of 中的 full 為形容詞，意為「滿的」，但 full of 的含意是 having or containing a lot of things or people or a lot of something，而 filled with 的含意是 making something full 或 becoming full of something，其中 filled 為動詞 fill 的過去分詞形容詞。由此可知，在這兩個片語中，只有 be filled with 能表達真正裝得滿滿沒有剩下任何空間的意思，而 be full of 是表示含有或裝有很多東西、許多人或大量的某種東西，相當於「都是；滿是」的意思。例如：
- The room was full of books. (這個房間都是書) (正)
The room was filled with books. (誤) － 除非這個房間沒有其他任何東西，而且書籍從地板疊到天花板，整個房間都堆滿書，這句才講得通。 - The restaurant is always full of customers. (這家餐廳總是門庭若市) (正)
The restaurant is always filled with customers. (誤) － 除非這家餐廳的客人摩肩接踵，大家擠成一堆，沒有任何移動或用餐空間，這句才講得通。 - His trousers are full of holes. (他的褲子都是洞) (正) － 褲子上有許多洞。
- Her essay was full of grammatical errors. (她的論文滿是文法錯誤) (正) － 論文中有許多文法錯誤。
- Her eyes were full of tears. (她眼中滿是淚水) (正)
- Her eyes were filled with tears. (她眼淚盈眶) (正)
- The room is filled with smoke. (這個房間煙霧瀰漫) (正)
再者，在這兩個片語中，只有 filled with 可與 grief (悲痛)、horror (恐懼)、shock (震驚)、terror (驚恐) 等表示強烈情緒的字眼連用，不可使用 full of。例如：
- Mary was filled with shock and grief when she found that her husband had an affair with a colleague at work. (當瑪麗發現她老公跟他同事有染時，她震驚不已、悲痛欲絕) (正)
Mary was full of shock and grief when she found that her husband had an affair with a colleague at work. (誤) - John looked at the teacher, filled with horror. (約翰充滿恐懼地看著老師) (正)
John looked at the teacher, full of horror. (誤)