气焊的火焰有中性焰、碳化焰、氧化焰三种。
参考答案：对
The image of a devoted and noble angel in white _____ heals the wounded and rescues the dying is making a comeback _____ the nation faces a crisis.
A．that…because
B．who…when
C．which…that
D．what…as
在下列Windows 98提供的多媒体组件中，与三维动画处理相关的是
A．OvenGL
B．MCI
C．VFW
D．DirectSound
