I HAVEN'T SEEN SUCH A STRANGE BEHAVIOR BEFORE

37. - BAI TAP TRAC NGHIEM HKI I GV
BAI TAP TRAC NGHIEM HKI I GV
37. I haven't seen such a strange behavior before. A. This is the first time I'm seeing such a strange behavior. B. This was the first time I had seen such a strange behavior. C. Such a strange behavior has never seen by me before. D. This is the first time I've seen such a strange behavior.