By Richard Lister, Washington

媒體英語會帶大家一起學習BBC撰稿人在報道世界大事時常用到的單詞和短語。

Background: 背景：一對美國夫婦在沒有受到邀請的情況下，不但混入了白宮而且還受到了總統奧巴馬的接見。此后，美國特情局決定將加強對在白宮內舉行官方活動的安防檢查。特情局已經發表了一份書面道歉聲明，稱其對未能嚴格執行安防措施深表歉意。白宮也表示其工作人員要監管來訪個人的工作更為負責任。美國國會晚些會舉行聽證會對此事件進行進一步調查。

Even with an invitation to the White House, it can be tricky to get through the heavily guarded perimeter.

So the revelation that a couple of aspiring socialites were able to talk their way into the state reception for India's prime minister last week, left officials scrambling for answers.

President Obama, who met the couple in a receiving line, was said to be angry about the incident and received a public apology from the Secret Service, which said procedures hadn't been followed at an entry point.

But now the White House deputy chief of staff, Jim Messina, has issued a memo instructing members of his team to be stationed alongside secret service agents at entry check-points, for all White House events.

Their role will be to cross-reference the guest list as people arrive.

The White House has declined a request to send the Obama social secretary to the forthcoming Congressional hearing on the matter.

It's unclear whether the couple who sparked this furore, Tareq and Michaele Salahi, will be attending, although this time they do have an invitation.