BBC在线收听下载:科学家称北极冰层融化速度惊人

短语讲解：

1. Scientists have warned that Arctic ice is melting at an unprecedented rate because of unusually high temperatures.

because of 因为，由于
例句：It is mainly because of my fault.
这主要是由于我的过错。

2. Mr Zuma is due to appear before the governing ANC’s integrity commission next week.

due to 由于; 因为
例句：The team's success was largely due to her efforts.
该队的成功在很大程度上是由于她的努力。