Answer:
Because experience has been compared to a 'lamp'.
Explanation:
Metaphor is the figure of speech in which comparison is made. The comparison is made between two things which are very different from each other. They are very different fro each other but there lies one aspect in common to them. The characteristic common helps in building a comparison between them. In the above excerpt, the experience of the writer is been compared with a 'lamp'. This is an example of a metaphor.
