She scrubbed (at) the mark on the wall for a long time, but it wouldn't come off.

她花了很长时间擦洗墙上的印迹，但仍然没有擦掉。

Her novel The Mark on the Wall written in 1919 is a successful novel of stream-of -consciousness.

她于1919年写的意识流小说《墙上的斑点》就是一个成功的范例。

And if I were to get up at this very moment and ascertain that the mark on the wall is really - what shall I say?

假如我在此时此刻站起身来，弄明白墙上的斑点果真是——我们怎么说不好呢?。