What is the important of the institutional hymn?​

What happens once in a minute twice in a moment and never in a thousand years?

My pretty rose tree by william blake a flower was offered to me, such a flower as may never bore; but i said, ‘i’ve a pretty rose tree,’ and i passed the sweet flower o’er. then i went to my pretty rose tree, to tend her by day and by night; but my rose turned away with jealousy, and her thorns were my only delight. what is the rhyme scheme of the two stanzas in this poem? a. abba, cdda b. abab, acac c. abab, cddc d. abaa, cddc

What element of medieval literature does the disappearance of the sword into the lake represent?