It's obviously not urgent they would have called us right away. A. butB. orC. soD. for

问题补充：

Its obviously not urgent they would have called us right away.

A. but

B. or

C. so

D. for

答案：

A. but

(答案→)B. or

C. so

D. for

解析：考察连接词。根据句意：很明显这件事情不紧急，要不然他们立刻就会打我们电话。可知应该选用or:否则，要不然。