She had to drop out of school her family couldn’t afford the cost of her education.
A. although
B. unless
C. because
D. so
网友回答
A. although
B. unless
(答案→)C. because
D. so
解析：连词辨析。A尽管；B除非,如果…不…;C因为；D于是；句意：因为家里承担不起教育的费用，他不得不辍学了。根据句意说明上下文是因果关系，横线后面表示的是愿意，故使用because。故C正确。