网络安全
参考答案:
是指确保网络上的信息不被非授权用户所使用,通常把为了保护数据及反黑客而设计的工具集合成为计算机安全。它强调的是网络中信息的完整性、可用性、保密性。
我国半湿润地区和半干旱地区的分界线大体上相当于下列哪一条等降水量线?[ ]
A.1600毫米
B.800毫米
C.400毫米
D.200毫米
用适当的情态动词填空。
1. _____ you like to share a room with
your sister?
2. Mum said to her baby" You _______ not eat so many candies. "
3. — You have so much work to do. _____.
— you like me to help you?
— No, thanks.
4. — ______ I finish the job tomorrow?
— No, you needn't.
5. — Could I use your computer?
— Yes, you _____.
6. — Need I go there with you?