Question

how does the poet tries to immortalise his friend in sonnet 55

Answer 1

According to the poet.........
A poetry is immortal...........it'll last till the doomsday......and the memory of his friend will remain with this poem forever....even after her death......no doubt, time is very powerful but it's not powerful enough to destroy this living record......and in this way poet tries to immortalize his friend!!!!
That's it!!!
Hope it helps!!