汽包内的旋风分离器和百叶都是汽水分离装臵，其中旋风分离器是（）次分离元件，百叶窗是（）次分离元件。
参考答案：一；二
企业的哪些文件应长期保存？
--_____wonderful time they had at the party!
– Yes. They sang, danced and enjoyed delicious food there.
A．What a
B．What
C．How
D．How a
