1
Firstly, ..., secondly, ...
用于列举步骤或论点。
Firstly, we need to gather data; secondly, we analyze it.
首先，我们需要收集数据；其次，我们分析数据。
第二；其次
先理解核心含义，再看它在真实句子里的用法。
第二；其次
secondly
Firstly, we need to gather data; secondly, we analyze it.
首先，我们需要收集数据；其次，我们分析数据。
第二点；其次。
In the second place.
其次,第二
in the second place
Firstly, we need to gather all the data; secondly, we will analyze it.
首先，我们需要收集所有数据；其次，我们将分析这些数据。
I have two reasons for declining: firstly, I am too busy; secondly, the project does not interest me.
我拒绝有两个原因：第一，我太忙；第二，这个项目不让我感兴趣。
The plan has several steps: firstly, research the market; secondly, develop a prototype; thirdly, test it.
该计划有几个步骤：首先，调研市场；其次，开发原型；第三，进行测试。
用于列举步骤或论点。
Firstly, we need to gather data; secondly, we analyze it.
首先，我们需要收集数据；其次，我们分析数据。
用于引出第二个原因或观点。
Secondly, the cost is too high for most people.
第二，对大多数人来说成本太高。
Not this
This is the secondly point.
Use this
This is the second point.
secondly是副词，不能用作形容词修饰名词；应用形容词second（第二）来修饰名词point。
Not this
He is the secondly tallest player on the team.
Use this
He is the second tallest player on the team.
secondly是副词，不能用于构成最高级中的序数；应用序数词second（第二）表示顺序。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
首先……其次
Firstly, I'll discuss the benefits; secondly, the drawbacks.
首先，我将讨论优点；其次，讨论缺点。
并且其次
We need to reduce costs, and secondly, improve efficiency.
我们需要降低成本，并且其次，提高效率。
其次，我们
Secondly, we should analyze the data.
其次，我们应该分析数据。
其次，有
Secondly, there is the issue of timing.
其次，还有时间安排的问题。
Use secondly naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
secondly = second + ly，记住“第二”加ly变成副词“其次”。
语境：列举顺序；语域：混合；说明：通常用于正式演讲或写作中列举第二点，口语中也可使用但不如'second'常见。
通常用于列举，位于句首，后接逗号。
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY.