1. 在语法上，"在第几行用英语怎么说"可以被看作是一个带有疑问词的复合句，其中"在第几行"是疑问词短语作为主语，"用英语怎么说"是谓语动词和宾语构成的问句。在教学中，需要给学生讲解复合句的构成和疑问词的使用。

例句：

- What's the correct way to say it in English in this line?

- Could you tell me how to say it in English in this line?

- I don't know where to put the English in this line, could you help me?

- The question of how to say it in English in this line remains unsolved.

2. 从词汇角度来说，"在第几行用英语怎么说"对应了英语中的"how to say in English in which line"或"what's the English expression in which line"等。教学中需要引导学生了解相关词汇的用法和搭配。

例句：

- Can you give me the English translation for this line?

- I'm not sure how to say this in English, can you give me some help?

- Could you please tell me where the English should go in this line?

- The English phrase for this line is quite tricky, can you help me figure it out?

3. 从实践角度来看，"在第几行用英语怎么说"意味着学生需要尝试运用所学的语言知识和技巧，根据具体的语境和需要来表达自己的意思。因此，教学中需要加强语言输入和输出的训练，鼓励学生积极参与交流。

例句：

- Let's practice how to say this in English in different lines.

- Can you come up with a few different English expressions for this line?

- You need to use English to explain this line to your partner.

- Write a short paragraph using English expressions for the lines we just learned.

4. 从交际角度而言，"在第几行用英语怎么说"反映了学生在实际交流中的需求和挑战。在教学中，需要给学生提供充分的机会和平台，让他们在多种交际场景中运用所学知识，并且引导他们探索有效的交际策略和技巧。

例句：

- In this role play, you need to use English expressions to guide the customer to the right product line.

- You will be giving a presentation in English, so you need to make sure you use the right expressions for each slide.

- In the group discussion, you need to ask and answer questions about the English expressions used in the text.

- You are going to write an email in English to your teacher, asking for guidance on the expressions used in your writing.