IT WAS NOT UNTIL THE 13TH STROKE(=KNOCK)...THE BELL STOPPED. A. SO...

95. - 99 NHỮNG CẤU TRÚC THƯỜNG GẶP TRONG BÀI THI DAP AN
99 NHỮNG CẤU TRÚC THƯỜNG GẶP TRONG BÀI THI DAP AN
95. It was not until the 13th stroke(=knock)...the bell stopped. a. so that b. that c. before d. when