a piece of

• Mary : a piece of cheese . a loaf of bread . a bar of soap .
  玛丽：一块干酪，一只面包，一块肥皂。
• She had fastened the door inside with a piece of string .
  她原先曾用了一根细绳儿把门从里面拴起来了。
• The old man wore an eyeglass attached to a piece of ribbon .
  那老人戴着单片眼镜，上面连结着一条丝带。
• Dee broke off a piece of limestone and thumbed it into the stream .
  迪伊掰下一块石灰石，用拇指弹进河里。
• He thought he ought to have a piece of it and he tried once again .
  他想他应该得到一块儿，所以他又试探着。
• In my office safe there is a piece of paper with your name on it .
  在我办公室保险柜里，有一份你签署的文件。
• The intrinsic value of a dollar bill is only that of a piece of paper .
  一元纸币的实际价值不过是一张纸而已。
• Take a piece of cardboard or stiff paper and hold it close to the globe .
  取一张纸板或硬纸片，拿到地球仪边。
• He burned a piece of sulphur which he had carefully weighed beforehand .
  他燃烧了一块预先仔细称过分量的硫磺。
• You have a piece of land on the other side of the river that i need .
  你有一块地皮在河那一边，正是我所需要的。