giúp với ạ

20. The old building ____________ is in front of my house fell down. A. of which B. which C. whose D. whom The correct answer is A. "of which" Explanation: In this sentence, we need to use a relative pronoun to introduce the relative clause that modifies "the old building". The relative pronoun should refer back to "the old building" and indicate possession. Option A, "of which", is the correct choice because it correctly shows possession and refers back to "the old building". Option B, "which", is incorrect because it does not show possession. Option C, "whose", is incorrect because it shows possession but does not refer back to "the old building". Option D, "whom", is incorrect because it is used for people as the object of a verb or preposition, not for objects like buildings. Exercise 5: Rewrite the following sentences by using the relative clauses 1. The house has been built in the forest. It doesn't have electricity. $$ The house that has been built in the forest doesn't have electricity. 2. Do you know the man? He is coming towards us. $$ Do you know the man who is coming towards us?