It will probably never be known whether you cracked a joke or indiscreetly emitted a rather rude noise.

But the result on the Buckingham Palace balcony was undoubtedly one of general hilarity - to all but the Queen.

As all eyes focused on Prince Philip as the source, Her Majesty was not amused.

While she gamely tried to maintain her poise and dignity, Philip, the Princess Royal and Princes Charles and Harry fought a losing battle to stifle their mirth.

Sideways glances and suppressed grins slowly gave way to open laughter. Harry even had to cover his face and duck out of view to hide his uncontrolled guffaws.

The Queen, however, adopted a stolid expression and flicked her eyes to her left in a look of reproach.

Perhaps the icy stare did the trick, for her giggling family soon regained their composure to watch a huge crowd applaud the Monarch's official 80th birthday.

Earlier, thousands lined The Mall in the sweltering heat to watch the traditional Trooping the Colour, made even more special this year because of the Queen's milestone anniversary.

The Monarch left Buckingham Palace in Queen Victoria's 1842 ivory carriage, seated next to Philip in his red tunic and bearskin hat.

无论你是开了个玩笑，还是轻率地放了个响屁，也许都不会被人知道。

但在白金汉宫的露台上这样做，结果铁定就是招来一场欢闹——王室成员全体笑翻，只有女王不在此例。

即使当所有人把目光投向这个放响屁的人--菲利普亲王时，女王也没有被逗乐。

女王尽力保持着镇静和尊严，而菲利普亲王、长公主、查尔斯王储和哈里王子已经忍俊不禁了。

刚开始，这几个人还挤眉弄眼、强压笑意，后来干脆大笑起来。哈里王子更是一发不可收拾，捂住脸，狂笑起来。

然而，此时的女王则一脸严肃，她看了看左边的这几个人，面露责备之色。

也许正是这冷淡的一瞥起了作用，刚才还在叽叽咯咯笑个不停的王室成员们很快平静下来，把注意力转向台下为女王庆祝80岁官方生日的人群。

此前，成千上万的人在酷暑中站在林荫大道两旁，观看皇家军队阅兵，由于女王的80岁寿辰意义非同寻常，所以今年的阅兵仪式更为隆重。

女王坐着维多利亚女王的1842年象牙马车离开白金汉宫，身着红色束腰外衣、头戴熊皮帽的菲利普亲王坐在她的身旁。

Vocabulary:

crack a joke : 开玩笑

grin : 露齿笑；咧嘴笑

duck out of : 巧妙的避开

guffaw : 狂笑；哄笑

do the trick: 获得成功；起到作用

Trooping the Colour : 皇家军队阅兵仪式