______birdsusetheirfeathersforflight,someoftheirfeather...
问题详情：
______ birds use their feathers for flight, some of their feathers are for other purposes.
A. Once B. If C. Although D. Because
【回答】
【*】C
知识点：连词
题型：选择题
问题详情：
______ birds use their feathers for flight, some of their feathers are for other purposes.
A. Once B. If C. Although D. Because
【回答】
【*】C
知识点：连词
题型：选择题
