简述影响计算机网络安全的主要因素有哪些。
参考答案:影响计算机网络安全的主要因素有如下几点: (1)人为的无意失误。 (2)人为的恶意攻击。 (3)网络软件的漏洞和“后门”。
— Has James finished his report on his Enquiry Learning yet?
— I'm not sure. She _____ on it last week. [ ]
A. was working
B. has worked
C. worked
D. had worked
在元朝时,许多信仰伊斯兰教的波斯人.阿拉伯人迁入中国,他们同汉.蒙古等族互相融合,形成一个新的民族是指:()
A.维吾尔族
B.回族
C.女真族
D.党项族