lose one's train of thought

Meaning

This idiom means to forget what one was speaking about or thinking about mid-sentence. It often happens during presentations, discussions, or lectures when a distraction occurs. It is a highly common conversational phrase.

Examples

• Sorry, the loud noise outside made me lose my train of thought.

  Sorry, the loud noise outside made me lose my train of thought.

• I was about to make an important point about the data, but I completely lost my train of thought.

  I was about to make an important point about the data, but I completely lost my train of thought.

• When the student interrupted with a question, the professor lost his train of thought for a second.

  When the student interrupted with a question, the professor lost his train of thought for a second.

• Let me check my notes because I just lost my train of thought.

  Let me check my notes because I just lost my train of thought.

• Don't distract her while she's presenting, or she'll lose her train of thought.

  Don't distract her while she's presenting, or she'll lose her train of thought.

Common Mistakes

• ✗ I lost my thought train during the presentation.

  ✓ I lost my train of thought during the presentation.

  The idiom is fixed as 'train of thought'. You cannot invert the words to 'thought train'.

• ✗ She lost her train of thoughts while speaking.

  ✓ She lost her train of thought while speaking.

  'Thought' must be singular in this idiom, not plural.

Related Expressions

Practice

• I'm sorry, what was I saying? I completely ___.

  💡 Forgot what I was talking about mid-sentence.

  Show answer

  lost my train of thought

• If you interrupt him now, he might ___.

  💡 Forget his line of thinking.

  Show answer

  lose his train of thought