打包贷款金额一般不超过信用证金额的80%，放款期限最长不超过信用证有效期后（）天。
参考答案：21
---I think Miss Gao must be in the library. She said she would go there.
---No, she ___________ be there. I have just been there.
A．can’t
B．mustn’t
C．needn’t
D．wouldn’t
因式分解4x4-64的结果为______．
