闪点的定义？
参考答案：
在规定的条件下，使易燃和可燃液体蒸发处足够的蒸气，以致在液面上发生闪燃的最低温度。
Not until most of the people had left the airport（）his sister was there.
A.that he saw
B.had he seen
C.did he see
D.that he had seen
服饰搭配是一项内在的（）活动。
A.心理
B.思维
C.品味
D.身心
