--He is so unhappy. What made him disappointed?

--It’s his plans. You can’t imagine what it’s like to feel that all your plans for the future have _________.

A．set down

B．turned down

C．put down

D．broken down

螺旋焊管调型操作时，2＃辊一般根据板材厚度和机械强度确定（）。

A、板宽

B、管径

C、递送力

D、压下量