Help Translate And Identify China Cover Scott 1987

Good evening Ladies and Gentlemen.

I need a little help translating and identifying this cover. It has souvenir sheet Scott #1987 affixed to it, and looks like it had been postaly used. However there is no pricing for used sheet in the catalog. My firs thought was that this is FDC, but the FDC on the web looks different. Maybe translating the cover will help with its identification. The cancellation stamp was applied in 1991, but the stamp was issued in 1987.

I will greatly appreciate any on this matter.

The sender was the Chinese Post Office, with an address in Beijing. The characters under 'U.S.A.' are simply 'USA' in Chinese.

I was trying to figure out why there was no actual address on this cover. Then, through the window, came the light. And all was understood.

Tony,

Thank you very much. This was very helpful.
So basically this is not an FDC or other commemorative cover. Just some odd one.

Thanks.

Afraid so ...