Choose the correct conjunction to complete this sentence: ______ the experiment data was incomplete, we postponed the analysis.
答案解析
Core concept: 连词使用。
解题思路: The sentence requires a causal conjunction.
选项分析: B. 'Since' introduces cause (correct). A. 'Although' shows contrast (illogical). C. 'Unless' sets condition (irrelevant). D. 'While' contrasts ideas (incorrect logic).
易错点: Mistaking coordinating conjunction for subordinator.
正确答案：B