but then

but then的音标是[bʊt ðen]，基本翻译是“但是，而且;既然;不过”。速记技巧是将其拆分为单词but和then来记忆。

But then 的词源：

But 是连词，表示转折关系，而 then 是副词，表示“然后”的意思。这两个词都是古英语时期引入的词汇。

变化形式：But 通常没有变化形式，而 then 可以根据语境和搭配的不同而变化，如 then 和 than 连用时，then 可以变为过去分词形式。

相关单词：

1. until 和 till 是与 but 和 then 相关的词汇，它们都表示时间上的转折关系。

2. before 和 after 也是与 but 和 then 相关的词汇，它们表示时间上的先后顺序。

3. again 和 over 是与 then 相关的词汇，表示重复或再次的意思。

例句：

1. We waited for an hour, but then we decided to leave.（我们等了一个小时，但是后来我们决定离开。）

2. I didn"t sleep well last night, but then again, I was nervous about the exam.（昨晚我没睡好，但是再一想，我对考试很紧张。）

3. After finishing my work, I took a break, but then I realized I had forgotten to do something.（完成工作后我休息了一下，但是后来我发现我忘了做某件事。）

总之，but 和 then 这两个词在英语中经常使用，它们表示转折和时间上的先后顺序关系，是英语中非常重要的连词和副词。

常用短语：

1. but then again

2. but even so

3. but on the other hand

4. but nevertheless

5. but eventually

6. but in the end

7. but then and again

例句：

1. But then again, we all have our own unique challenges to face.

2. But even so, I"m still determined to pursue my dream.

3. But on the other hand, I"m not giving up easily.

4. But nevertheless, I"m going to try my best to overcome this obstacle.

5. But eventually, I"m going to succeed in achieving my goal.

6. But in the end, I realized that persistence is the key to success.

7. But then and again, I wonder if I"m making the right decision.

英文小作文：

Life is full of ups and downs, but then again, it"s what we make of it that matters. Sometimes we face challenges that seem insurmountable, but with persistence and determination, we can overcome them and emerge stronger than before. However, life also brings us moments of joy and happiness, and these moments are what make life worth living. We should cherish every moment of our lives, no matter what challenges we face, because life is a journey worth taking.