Though great efforts have been ________on her study,Annie can’t still make any improvements,which makes her parents greatly________.

A．made;surprised

B．done;surprising

C．taken;surprised

D．given;surprising

冷却器外径为700mm，内设置φ25×2.5管子121根（单程），水在管内流动，每小时水量为30m³，求水在管内的流速？