如图所示，当体操运动员从高处落下，与蹦床接触的过程中，蹦床表面发生 ，而获得 能。
形变；弹性势
—Where was the boy taken away by the UFO?
—Oh, it was in the lake ______ he was swimming.[ ]
A. that
B. where
C. because
D. at which
. The prices have been going up, so that the richer you get, the less rich you are than ________ you think you ought to be.
A．that
B．/
C．what
D．which
