Combine the following pairs of sentences using a 'preposition + whom / which' or a 'quantifier + of + whom / which'. (cẩn thận những câu là "Non-defining relative clauses" thì nhớ phải thêm dấu phẩy):
LƯU Ý: NHÌN KỸ ĐỀ RỒI MỚI TRẢ LỜI! TUYỆT ĐỐI KHÔNG COPY MẠNG VÌ CÂU HỎI CỦA MÌNH CÓ THỂ HƠI KHÁC!
17. There wasn't any directory in the telephone box. I was phoning from this box.
-> .....................................................................
18. Graham took us to his office. It was filled with books.
-> The office.....................................................
17. There wasn't any directory in the telephone box from which I was phoning.
18. The office to which Graham took us was filled with books.