You'll have to pay excess postal charges on this letter.

这封你必须付超重。

All letters must be stamped with the correct postage.

任何件都应该按所需票。

An aerogramme is writing paper, envelope, and postage all-in-one.You can get aerogrammes at any post office.

航空就是纸、封和全在一的件，你可以在任何一个局买到航空。

Price $14.90, postage included.

14.90美元，包括在内。