车辆在高速公路上行车时，可以频繁地变更车道。

I think, the Chinese teacher will surely give _____ on your composition.

A．sense

B．comment

C．comments

D．idea

小小解说员（解释下列词语）。

(1)相依为命：                                                                                                                                  

(2)欣欣向荣：                                                                                                                                  

(3)郑重其事：                                                                                                                                  

(4)束手无策：                                                                                                                                  

(5)垂头丧气：                                                                                                                                  

(6)胸有成竹：                                                                                                                                 

2009年春季，华为技术有限公司和国内运营商共同署名的RFC标准——RFC5316和RFC5392被IETF标准组织作为最高级别的推荐性标准发布。这是我国在（）领域首发的RFC标准。

A．IP交换

B．IP路由

C．MPLS交换

D．MPLS路由

最适合制汤的鸡是笋鸡。

在NH₃·H₂O中加入一些NH₄Cl晶体，则下列说法正确的为( )。

A．NH₃·H₂O的电离增加

B．NH₃·H₂O电离常数kb增大

C．溶液的pH值减小

D．溶液的pH值增加