Not all, there are 5 of them that have rust stains.

不是全部，五辆有锈斑。

Are they blood stains, or mud stains, or rust stains, or fruit stains, or what are they?

这些斑点究竟是血迹呢，还是泥迹，是铁锈还是果汁的痕迹呢，还是其他什么东西？

But our experts are of the opinion that the rust stain are not due to dampness but to poor workmanship.

但是我们的专家认为，锈斑并不是由于受潮所致，而是由于手工艺粗糙造成的。