size = 1000000;
top = 1;

while (top <= Bottom) {
  b = top + size - 1;
  if (b > Bottom) {
    b = Bottom;
  }
  SelLeft = 1;
  SelRight = 10;
  SelTop = top;
  SelBottom = b;
  Copy();
  MessageBox(top + " 行目から " + b + " 行目までをコピーしました。");
  top = b + 1;
}