By means of “_____,” Whitman believed, he has turned the poem into an open field, an area of vital possibility where the reader can allow his own imagination to play.

By means of “_____,” Whitman believed, he has turned the poem into an open field, an area of vital possibility where the reader can allow his own imagination to play.

A.balanced structure

B.free verse

C.fixed verse

D.regular rhythm

正确答案是B