所有二十七国的国旗都在大楼外飘扬。

___Flags of all twenty-seven countries are flying outside the building.

警卫挥动他的旗子，火车驶离了车站。

The guard waved his ___flag and the train pulled away from the station.

关于我从美国收到的礼物：我真的很想有一面正宗的美国国旗，来装饰我卧室的天花板。

And about my present from the USA: I really would like to have an authentic American ___flag, to decorate my bedroom ceiling.