x

• It is almost the case that each x ray source exhibits its own brand of variability .
  几乎每个x射线源都有自己的变化特点。
• We focus our attention on the circled x's which signal redundancy .
  我们所关注的是有（x）标记处，这表明是一个多余的关系。
• Serr and forde used 9 x 15cm bags of tightly woven white cotton gabardine.
  塞尔和福德应用了9X15厘米的密绩白色棉华达呢袋。