甲
乙
原料限额
A(吨)
2
5
10
B(吨)
6
3
18
我国自主研制的“蛟龙号”载人潜水器成功深入7000米海底,创造了中国载人深潜的新历史;“天宫一号”与“神舟八号”两次交汇对接取得圆满成功……这些科技成就说明 ( )
Ben was busy taking a training class, ________ we had to wait for him for half an hour.