We all consider significant that we should cancel the order immediately.A. howB. whichC.

问题补充：

We all consider significant that we should cancel the order immediately.

A. how

B. which

C. this

D. it

答案：

A. how

B. which

C. this

(答案→)D. it

解析：句意：我们都认为我们应该立刻取消命令这很重要。这句话使用了：consider it+形容词+that从句，it是形式主语，that引导的是真正的宾语从句，选D。