throw in:to include sth with what you are selling or offering, without increasing the price (不提高售价或报价的)奉送,额外赠送,白搭
You can have the piano for $200, and I'll throw in the stool as well.
你花 200 元就可以买走这架钢琴,另外奉送这张琴凳.
make a payment:付款
within a ... day period:在...天期限之内
grace period:宽限期
put down on paper:写在纸上
go ahead:to happen; to be done 发生;进行
The building of the new bridge will go ahead as planned.
新桥的修建将按计划进行.
