报价Offer
买方接到供货商的购货报价后，对价格有些意见，于是向供货商还价。但买方表现得相当坚决，我们可以从以下会话得知：

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.

句型总结
●　我必须说明...
1. I must point out...
2. I must make it clear...
3. I must tell you...

"must"，‘必须’；"point out"，‘指出，特别说明’；这个句型之后可接"that"子句。"must"这个助动词使说话者的语气变得十分坚决，比"have to"与"should"都强烈，用于要求对方绝对遵守约定时。

短语解说
selling offer 售货报价，销货要约
"offer"，‘报价’；"selling offer"，又称"offer to sell"，是指卖方为销售货物，主动发给买方的报价。一般报价，大多是如此。

counter offer 反报价；还价
"counter"，形容词，意思是‘相反的、相对的’。‘反报价’是指被报价人不能完全接受报价人的条件，但尚有交易意愿，乃将原报价修改，或附加新条件，再反过来向原报价人是出新报价。法律上视为‘新约’；贸易实务上则视为‘新报价’，此时原报价则失效。

buying offer 购货报价
这是买方为购买货物，主动向卖方发出的报价。又称"purchasing offer"或"bid"（出价）。与"selling offer"正好相反。

the offer is valid until... 报价有效期限到...
"valid"，‘有效的、正当的’；"until"，‘直到’，后面按时间日期。这是报价时常用的句型，意在提醒对方尽快回复，以免延误时效。关键词为"valid"。