问题补充：
----Why is he feeling down today?
----Because the suggestion he has been turned down.
A. put away
B. put up
C. put down
D. put forward
答案：
A. put away
B. put up
C. put down
(答案→)D. put forward
解析：A. put away收好，储存，B. put up竖立，张贴，C. put down 放下，记下，D. put forward提出，句意：--为什么他今天感觉沮丧？--因为他提出的建议被拒绝了。根据句意选D.
