VOA慢速英语:Black Death Older Than We Thought

短语讲解：

1. The Black Death killed at least a third of the European population in the mid-1300s.

at least 至少
例句：In fact it requires at least n generators.
事实上，它至少要有n个元素。

2. Danish researchers discovered new evidence that the bacterium responsible for the plague infected people thousands of years earlier.

thousands of 数千的
例句：A computer consists of thousands of components.
电脑由成千上万个部件组成。

3. The researchers said the disease could have led to the collapse of Classical Greece and weakened the ancient Roman army.

lead to 导致; 把…带到; 领到
例句：That may lead to a serious split in our class.
那可能导致我们班的严重分裂。

4. The researcher Simon Rasmussen says disease may also have led to a number of ancient mass migrations, or people moving from one place to another.

a number of 一些; 许多的
例句：They found a number of simple expediencies to dissolve the contract.
他们找出了许多解除合同的简便方法。