Please explain the last two lines of "Sonnet 18" by William shakespeare.
What the last two lines of this sonnet mean is that Shakespeare is bragging about the importance of his work and of this poem in particular.
In the rest of the poem, he has talked about (among other things) how brief and transient a summer's day is. Then he has contrasted that with how his love will be immortal. He has said that she will never die because he has written this poem about her (that is what the line just before the couplet is saying).
In the couplet, he completes the thought by saying that as long as people exist, this poem will exist and she will live in the poem.
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