公钥加密体制中，没有公开的是A．明文 B．密文 C．公钥 D．算法_爱下问搜题

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问题单项选择题

公钥加密体制中，没有公开的是

A．明文

B．密文

C．公钥

D．算法

答案

参考答案：A

解析：在公钥加密体制中，没有公开的是明文。

选择题

欲称出质量39克的物体，应顺次往天平的右盘中添加砝码是（　　）

A．30g、9g

B．20g、10g、5g、2g、2g

C．30g、5g、4g

D．20g、10g、9g

填空题

根据句意，写出括号内所给单词的适当形式。
1. Do you think it's good for you to keep worries to _____ (your), boys and girls?
2. In China, it's becoming much _____ (hard) for people to pass the driving tests.
3. The government has realized the importance of the _____ (safe) of the children who take a school bus.
4. More and more teachers feel worried about some _____ (teenage) strange behaviour.