他疲惫不堪，直接瘫倒在椅子上。

He was so tired that he ___slumped into the chair.

由于经济衰退，房价急剧下跌了15%。

Housing prices ___slumped by 15% due to the economic downturn.

公司销售额连续三个月下滑，陷入了严重的不景气期。

The company's sales have been declining for three months straight, stuck in a serious ___slump.