英语语法分析

The retractions follow a separate one, two years ago, of a paper by Dr. Buck that was published in the journal Nature in 2001.

本次撤回事件发生的两年之前，巴克博士已经撤回了一篇2001年发表在《自然》杂志上的论文。

In the meantime, more retractions are coming, according to Dr Califf.

与此同时，按照卡利夫博士的说法，还会有更多的论文被撤回。

Retractions are when you can see the ribs when your child is trying to breathe.

三凹征指的是，当你孩子试着努力呼吸时，你可以看到肋骨。