Fill in the blank: “He is knocking _______ the door.”
Fill in the blank: “He is knocking _______ the door.”
(A) On
(B) Of
(C) Over
(D) At
Correct option is (D) At. The correct preposition to fill in the blank is “at”. In English, “knocking at the door”is the standard phrase used to described the action of making a sound by hitting the door to get someone’s attention. The preposition “at” indicates the location of the knocking. So, the sentence should be: “He is knocking at the door.”