Generally, the host doesn't open the gift in front of the guest, but waits until the guest has left to open it.

　　客人送上了禮物之后，收禮的人一般不當面把禮物打開，而是等到客人離去后才打開。

　　The agreement will open the door to increased international trade.

　　此協議將會提供增加國際貿易的機會。

　　This new job could open up whole new vistas for her.

　　這項新工作可能給她開辟全新的前景。

　　The new sports complex is on target to open in June.

　　新建的體育中心將在六月份如期開放。