He expressed a hope _______ he would visit China again the next year, and this was the very hope ________ he would express as soon as he arrived in the country.

A．that; that

B．which; which

C．that; which

D．which; that

以下关于网络系统安全的描述中，错误的是（）。

A．以商业宣传为目的的广告软件可能成为病毒、间谍软件和网络钓鱼的载体

B．可以通过身份认证、数字签名、数字信封、第三万确认等方法来防止抵赖现象

C．网络安全漏洞的存在是不可避免的，应及时提出对策与补救措施

D．与非服务攻击相比，服务攻击与特定服务无关