答案：B

B。按英语习惯，在easy, difficult, impossible, good, ready等少数形容词后接不定式时，尽管句子主语与其后不定式之间为被动关系，不定式习惯上仍用主动形式。如：Both these questions are easy to answer. 这两个问题都容易回答。 English grammar is not very difficult to learn. 英语语法不很难学。 Are these berries good to eat? 这种莓子能吃吗? The letters are ready to sign. 这些信可以签字了。