If a person, company, or country defaults on something that they have legally agreed to do, such as paying some money or doing a piece of work before a particular time, they fail to do it.【不履行;未支付】
①The credit card business is down, and more borrowers are defaulting on loans.
②The first warning signals came in March when the company defaulted on its initial payment of £30 million.
这是一个超级高频的表达，《新闻周刊》一篇题为 Student debt is a curse upon America's future. Biden must wipe it out 的文章出现了两次：
同样，《新闻周刊》一篇题为 Biden's student loan forgiveness will make things worse 也出现了这个表达：
除此之外，我们平时最常见的关于“default”的意思可能是作为形容词，表示“默认的 ”【A default situation is what exists or happens unless someone or something changes it.】
①by default (事情的发生)自动地(因可能阻止或改变结果之事未发生) 【If something happens by default, it happens only because something else which might have prevented it or changed it has not happened.】
I would rather pay the individuals than let the money go to the State by default .
②in default of 因…未发生;因…不可能 【If something happens in default of something else, it happens because that other thing does not happen or proves to be impossible.】
Malvolio becomes, in default of competition, the play's moral centre.
zoom in （on）
If a camera zooms in on something that is being filmed or photographed, it gives a close-up picture of it.
①The spotlight zoomed in on him.
②He trained his camera on nature, sometimes zooming in to examine single leaves.
《科学美国人》一篇题为 In every bit of nothing, there is something 的文章也出现了这个表达：