—Mike didn’t notice the sign it was right in front of him.—How careless he is!A. because

问题补充：

—Mike didn’t notice the sign it was right in front of him.

—How careless he is!

A. because

B. but

C. though

D. unless

答案：

A. because

B. but

(答案→)C. though

D. unless

解析：句意：迈克没有注意到标识尽管就在眼前。他多么粗心呀！because因为； but但是； though尽管； unless除非 。所以选C。