Officials do not know why the 147-year-old clock on the banks of the River Thames stopped at 10:07 p.m. Friday.

　　It resumed keeping time, but stalled again at 10:20 p.m. and remained still for about 90 minutes before starting up again, a spokeswoman for the House of Commons said on condition of anonymity.

　　There has been speculation a recent spell of hot weather may have been to blame. Temperatures in London reached 90 Saturday, and forecasters called it England's hottest day in May since 1953.

　　Big Ben, which is operated by the Palace of Westminster, survived attacks by German Luftwaffe bombers during World War II, continuing to mark the time to within 1 1/2 seconds of Greenwich Mean Time.

　　However, the clock has experienced occasional problems.

　　In 1962, snow caused the clock to ring in the New Year 10 minutes late. In 1976, the clock stopped when a piece of its machinery broke. Big Ben also stopped on April 30, 1997, and once more three weeks later.

　　Big Ben is actually the clock's 13-ton bell, which was named after Sir Benjamin Hall, the British commissioner of works at the time the clock was built.

　　The official name for the Gothic tower holding Big Ben is St. Stephen's Tower. Standing 315 feet tall, it was completed in 1858 after an 1834 fire destroyed most of the Palace of Westminster.

　　(Agencies)

　　伦敦地标大本钟一向以报时精准、钟声悠扬而闻名于世，但一名工程师上周六表示，它居然出人意料地停摆了90分钟。

　　这座矗立在伦敦泰晤士河畔的大钟已有147岁高龄了，官员们很纳闷，不知道上周五晚10时07分它为什么突然罢工了。

　　停了一会它的指针又重新开始移动，但到了10时20分再次停了下来，这一停就是90分钟，英国国会下议院的一位不愿意透露姓名的发言人这样说。

　　有种推测认为，伦敦最近酷热的天气是罪魁祸首。上周六伦敦的气温高达90华氏度（摄氏32度左右），天气预报员称之为自1953年以来伦敦五月份气温最高的一天。

　　在威斯敏斯特宫内运转的大本钟曾在二战期间经受过德国空军的炮火袭击，但它仍然勤勉报时，和格林威治标准时间之间的误差从未超过1.5秒。

　　然而，这只“大笨钟”偶尔也会犯错。

　　1962年，由于指针上的积雪，大本钟晚了10分钟才敲响新年钟声；1976年，由于一小片零件出了故障，大本钟也一度停摆。1997年4月30日大本钟再次罢工，而且三周后又停了一次。

　　大本钟实际上是这口大钟13吨重的“铃铛”部分，是以本杰明·霍尔爵士的名字命名的，他是当年铸造这口钟时监督工程的英国专员。

　　大本钟所在的哥特塔式建筑的正式名字叫作圣·斯蒂芬塔，该塔高315英尺，于1858年全部完工，之前1834年的一场火灾将威斯敏斯特宫烧毁大半。