发电机是利用 ____现象制成的,发电机发电过程把机械能转化为 ____能.
下列有关物质性质的应用正确的是( )
— Did you enjoy____ (you) at the concert?
— Yes, I enjoyed ____ (listen) to music all the time.
如图:△ABC中,∠C=90°,AC=BC,AD平分∠CAB交BC于D,DE⊥AB于E,且AB=6㎝,则△DEB的周长是( )