Busy he was, he managed to spare some time to help plan the project.
A. while
B. although
C. as
D. when
网友回答
A. while
B. although
(答案→)C. as
D. when
解析：考查as的倒装。根据句意：尽管他很忙，但总是能腾出时间帮忙计划这个项目。开头有了busy，所以引导句子的连词只有用as可以引导倒装。while和although只能引导正常语序的状语从句。所以答案选C。