Most birds have paper thin abdominal muscles.

鸟类大多都有一层薄薄的腹肌。

So the secret here is really to get those apples paper thin.

所以这里的秘诀是让那些苹果纸薄。

The walls between our bedrooms are paper thin.

我们卧室间的墙壁像纸一样薄。

Keep your voice down – the walls are paper thin.

【thin，thinness】小声点——墙壁很薄。

Like so many who had grown up in the shadow of the second world war, though, he knew that the difference between being ok and not ok was paper thin.

但是，就像很多在二战的阴影中长大的人来说，他知道好与不好的关系就像纸一样薄。