half a century ago的意思|示意

There are about 10, 000 of these animals in North America. All of them are descended from an original population of just 30 that was introduced half a century ago.

在北美这种动物现存一万只左右，他们全部都是由半个世纪以前的一个的物种进化而成，当时这个物种的数量只有三十只。

Don also found unopened letters that Mr. Brick's mother had sent more than half a century ago.

唐还发现几封布瑞克先生母亲超过半个世纪前寄来的未开封的信。

Half a century ago it claimed 25,000 researchers and its own physics laboratory.

半个世纪前仅其物理实验室就有2万5千名研究员。

Rich in teak, minerals, oil, gas and much else, half a century ago Myanmar was one of the more prosperous countries in the region.

凭借着丰富的柚树、石油、天然气和其他资源，缅甸半个世纪以前曾是东南亚区域内相对富有的国家之一。

That question, posed by Jack Kerouac on behalf of the Beat generation half a century ago, is the biggest uncertainty hanging over the world economy.

半个世纪前，杰克·凯鲁亚克代表垮掉的一代提出了这个问题。它表明了当今世界经济的最不确定性，也反映了美国选民们的最大担忧。

With their famous names and skilled workers, Britain's universities are in the same state as its motorbike-makers and Banks were half a century ago.

英国大学正遭遇和半个世纪以前声名显赫且人才济济的英国摩托车制造商以及银行业的一样的境况。