She didnt go to the party last night she had to finish her term paper.A. ifB. thoughC.

问题补充：

She didn go to the party last night, she had to finish her term paper.

A. if

B. though

C. till

D. because

答案：

A. if

B. though

C. till

(答案→)D. because

解析：本题考查对主从句逻辑关系的理解。主句说她没有参加昨晚的晚会，从刨说她要完成学期论文，显然是解释她不能参加昨晚的晚会的原因，因此应该选表示原因的because。