Q: 26 files, last one added on sep 28, 2007
A: 26 files, last one added on Sep 28, 2007

Q: copper, refined, in the form of cathodes and sections of cathodes
A: Copper, refined, in the form of cathodes and sections of cathodes

Q: the tumor grows quickly, is likely to spread into nearby tissue, and the tumor cells look very different from normal cells.
A: The tumor grows quickly, is likely to spread into nearby tissue, and the tumor cells look very different from normal cells.

Q: in the diagram d is the diameter of the circle, a is the length of the arc ab and x is the length of nb which guo wanted to calculate.
A:
In the diagram d is the diameter of the circle, a is the length of the arc AB and x is the length of NB which Guo wanted to calculate.