x ray
X光，X射线

But a little more than a century ago, x ray machines provided a revolution in medicine, allowing doctors to look inside the body.
但是，仅仅是一百年前，X光机才刚刚改变了人类医学史，让医生能够看到人身体内部的情况。
Because of the wavelength of the x rays used, soft x ray microscopes will never match the highest resolution possible with electron microscopes.
由于使用的X射线的波长使软性X射线显微镜永远比不上电子显微镜可能具有的最高分辨力。