A:2 –乙基– 3,3 –二甲基戊烷
B:3,3 –二甲基– 4–乙基戊烷
C:3,3,4 –三甲基己烷
D:3,4,4 –三甲基己烷
—Did you have fun _____________ on your last day off?
—No, I didn't. there were too many people and it was really crowded.