IT WAS NOT UNTIL HE WAS 30 _______ HE KNEW HOW TO SWIM.A. WHEN B....

16. - File thứ 1: DE VA DAP AN ANH 10 BAI 2, KY 2
File thứ 1: DE VA DAP AN ANH 10 BAI 2, KY 2
16. It was not until he was 30 _______ he knew how to swim.A. when B. that C. what D. where