He……….off alone a month ago, and……….of since. A. set - hasn't been heard B. setted - hasn’t heard C. set - hasn't heard D. setted - hadn’t been heard19/30He……….off alone a month ago, and……….of since.set - hasn't been heardsetted - hasn’t heardset - hasn't heardsetted - hadn’t been heardGiải thíchChọn A