In any careful study of English usage, attention to detail can reveal subtle errors that change meaning or obscure intent. Here we examine four sentences that employ relative pronouns and adverbial phrases, and show why only one of them fails to convey its message correctly.

The first sentence reads “The man whom I respect most is my father.” In this case, “whom” serves properly as the object of the verb “respect,” and the structure is both formal and precise.

The second sentence states “That is the house in which he lived.” The preposition “in” logically refers to “house,” and linking it with “which” produces a clear, correct relative clause.

The third sentence declares “I well remember the day on which we both met.” Here “on which” replaces the more common “when,” and “I well remember” simply emphasizes the strength of the memory. The form is archaic but grammatically sound.

The fourth sentence, however, reads “Please tell me that all you know.” As phrased, it appears to ask the listener to assert the fact “all you know” rather than to communicate the content of their knowledge. English idiom requires a direct object such as “everything you know” or “all that you know.” Either of these alternatives restores clarity, for example: “Please tell me everything you know” or “Please tell me all that you know.”

Only the fourth sentence contains a mistake. Its correction lies in repositioning the object of “tell me” so that it unambiguously requests the information held by the listener.