The possibility pleasant smells might reduce pain has recently been suggested by new rese

The possibility pleasant smells might reduce pain has recently been suggested by new research.
A. where
B. what
C. which
D. that

A. whereB. whatC. which(答案→)D. that解析：考查同位语从句，同位词是The possibility，从句是对The possibility内容的说明，用that连接同位语从句，that只起到连接的作用，不做成分。句意：最近的研究说明愉快的味道可以减少疼痛的可能性。选D。

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