Robert Frost wrote in both（ ）and the free verse, and sometimes he wrote in a form that borrows freely from the merits of both.
A、blank verse
B、sonnet
C、rhyming couplets
D、the metrical forms
【正确答案】：D
【题目解析】：罗伯特·弗罗斯特以格律形式和自由体两种形式写作，有时他以一种自由借用两者优点的形式写作。
