--- Has he returned the book to our library?
--- No. He has _______ it for several months.
A:borrowed
B:lent
C:kept
D:bought
①部曲 ②家丁 ③家兵 ④护卫
已知两个相似三角形的对应边长分别为9cm和11cm,它们的周长相差20cm,则这两个三角形的周长分别为( )