补全对话。

根据所给情景完成对话，每空一词。

A:Jim,do you know when Mother's Day is?I think it's next Tuesday,   1   I'm not sure.

B:Yeah,that's right.It's next Tuesday. Do you    2    to get Mom a present?

A:Yes,but I'm not sure   3   to buy for her. Do you have a good    4   ？

B:How    5   a nice dinner? I'm sure she'll be   6   if you cook her a nice dinner.

A:I don't think so.I can't cook well because I am not  7    in cooking.

B:OK.What about a new dress?    8    she have a new dress now?

A:Hmm,l'm not sure    9    that's a good idea.I think I'll   10   to Dad. I'm sure he'll know what Mom likes.

1.______2.______3.______4．______5.______6．______7.______8.______9.             10.            

破密者面临多种不同的问题，其从易到难排列依次为( )。

A．仅知密文、已知明文、选择明文
B．己知明文、仅知密文、选择明文
C．已知明文、选择明文、仅知密文
D．选择明文、已知明文、仅知密文