Which two sections of the poem express the view that life is too short and we should enjoy it while we can?

loveliest of trees
by a. e. housman

loveliest of trees, the cherry now
is hung with bloom along the bough,
and stands about the woodland ride
wearing white for eastertide.

now, of my three score years and ten,
twenty will not come again,
and take from seventy springs a score,
it only leaves me fifty more.

and since to look at things in bloom
fifty springs are little room,
about the woodlands i will go
to see the cherry hung with snow.

The answer would be sections 2 and 3.

The author starts the poem conveying the beauty of nature and how it reminds him, at the same time, of the fleeting aspect of life. In the second stanza, he develops a sort of calculation of his own mortality and how close he is to the end. There's a strong irony here in how nature's grace and splendor serves to remind him of death. In the third and final stanza, he concludes that he should carry on living with intensity every moment as an antidote for life's brevity.

Hope this helps!

showing or having an insensitive and cruel disregard for others. (so basically being heartless)

hope this : )