法律所规定的电子签名是指（）

A、在纸质材料上的手写签名 

B、数据电文中以电子形式所含、所附用于识别签名人身份并表明签名人认可其中内容的数据。 

C、在纸质材料上的印鉴、印章等 

D、个人藏书签名

用所给词的适当形式填空

1. Lily isn't tall enough _________ (reach) the apples on the tree.

2. She found it difficult _________ (finish) her homework before 8 pm.

3. You'd better _________ (tell) me the news now.

4. Could you please give me some _________ (advice)?

5. I saw Betty _________ (read) in the classroom when I walked past.