Reread this couplet from the poem “nothing gold can stay.” so dawn goes down to day. nothing gold can stay. how does the image in these lines convey the idea that the best things in life should be appreciated while there's time?

A sunrise is one of the most beautiful things to view, but it does not last very long. The sun rises and dawn becomes a regular day with the sun in the sky. This image of a beautiful sunrise quickly ending conveys the idea of how the magnificent sight should be appreciated while it lasts.

glamis thou art, and cawdor; and shalt be what thou art promis'd; yet do i fear thy nature; it is too full o' the milk of human kindness to catch the nearest way: thou wouldst be great; art not without ambition; but without the illness should attend it. what thou wouldst highly, that wouldst thou holily; wouldst not play false, and yet wouldst wrongly win: thou'dst have, great glamis, that which cries, "thus thou must do, if thou have it: and that which rather thou dost fear to do than wishest should be undone." hie thee hither, that i may pour my spirits in thine ear; and chastise with the valor of my tongue all that impedes thee from the golden round, which fate and metaphysical aid doth seem to have thee crown'd withal.  

he lacks ambition.  

he is hesitant.  

he lacks courage.  

he has moral scruples.