【单选题】The girl was fined $ 20 for failing to keep her dog _________ .
【单选题】The girl was fined(罚款)$20 for failing to keep her dog .
【单选题】下列电光源中属于热辐射电光源的是( )。
【单选题】The girl was fined(罚款)200 for failing to keep her dog .
【单选题】The girl was fined $20 for failing to keep her dog ____.
【单选题】一切能产生光辐射的辐射源都称为光源,下列光源中属于热辐射光源的是:()