''A little learning is dangerous Drink deep or taste not the Pierian spring'' The extract illustrates a

The extract "A little learning is dangerous, drink deep or taste not the Pierian spring" illustrates a couplet. A couplet is a pair of successive rhyming lines in poetry, usually of the same length. In this case, the couplet is made up of two lines that are both advice about the dangers of incomplete knowledge, with the second line building on the first.