_____to his research work, the professor cared little about any other things．

A．Devoting

B．Devoted

C．Having devoted

D．To devote

我国洁净室室内发尘量是以( )计算的。

A．每平方米发尘量地板面积

B．每人每分钟发尘量

C．单位容积发尘量

D．各尘源发尘量之和