報價Offer
買方接到供貨商的購貨報價后，對價格有些意見，于是向供貨商還價。但買方表現得相當堅決，我們可以從以下會話得知：

英文正文
A: Your selling offer sounds good, but we'd like to place some of the details under negotiation.

B: We understand that our selling offer was simply to open the negotiations. Can you give us the details of your counter offer?

A: Well, in our buying offer we would like to ask for 10 percent off your prices if we place orders over 5000 units per month.

B: Well, that sounds reasonable, but I can't make a decision yet. I must discuss it with my boss.

A: That's fine. But I must point out that the offer is only valid until the end of the month.

B: I understand fully. I promise to get back to you as soon as possible with a counter offer.

A: I must make it clear that there can be no counter offer. The answer must be either yes or no. If no, we'll look for another supplier.

句型總結
●　我必須說明...
1. I must point out...
2. I must make it clear...
3. I must tell you...

"must"，‘必須’；"point out"，‘指出，特別說明’；這個句型之后可接"that"子句。"must"這個助動詞使說話者的語氣變得十分堅決，比"have to"與"should"都強烈，用于要求對方絕對遵守約定時。

短語解說
selling offer 售貨報價，銷貨要約
"offer"，‘報價’；"selling offer"，又稱"offer to sell"，是指賣方為銷售貨物，主動發給買方的報價。一般報價，大多是如此。

counter offer 反報價；還價
"counter"，形容詞，意思是‘相反的、相對的’。‘反報價’是指被報價人不能完全接受報價人的條件，但尚有交易意愿，乃將原報價修改，或附加新條件，再反過來向原報價人是出新報價。法律上視為‘新約’；貿易實務上則視為‘新報價’，此時原報價則失效。

buying offer 購貨報價
這是買方為購買貨物，主動向賣方發出的報價。又稱"purchasing offer"或"bid"（出價）。與"selling offer"正好相反。

the offer is valid until... 報價有效期限到...
"valid"，‘有效的、正當的’；"until"，‘直到’，后面按時間日期。這是報價時常用的句型，意在提醒對方盡快回復，以免延誤時效。關鍵詞為"valid"。