Don’t give up working hard you’ll be successful some day.A. orB. and C. butD. so

问题补充：

Don’t give up working hard, you’ll be successful some day.

A. or

B. and

C. but

D. so

答案：

A. or

(答案→)B. and

C. but

D. so

解析：考查连词and/but/or的用法。句意“不要放弃努力，有一天你就会成功。”or“否则”，表转折；and“并且”，表递进；but“但是”，表转折；so“所以”，表因果。故选B。