_________(61)A.change B.changingC.to change D.bei

_____ is the circulation and refreshing of the air in a space without necessarily a change

The word "move" underlined in Paragraph 6 means to ______ .A．change position or placeB．tak

The word "move" underlined in Paragraph 6 means to ______ .A．change position or placeB．tak

The discharge head of a centrifugal pump will vary directly with the _____.A.change in imp

_________(57)A.change B.hydrogen C.oxygen D.memory

_________(61)A.change B.addC.switch D.shift