VOA慢速英语:Scientists Work to Understand Earth's Magnetic Field

短语讲解：

1. Most of us rarely think about the earth's magnetic field.

think about 考虑…; 捉摸…
例句：What do you think about the shipment?
你对货运是怎么考虑的？

2. What we do know is the earth's magnetic field has reversed north-south hundreds of times in earth's history.

hundreds of 好几百，许许多多
例句：Money to the extent of hundreds of thousands was set in motion.
流通的金钱达几十万金元之多。

3. Mr. Lathrop and his team are trying to find out how and why that happens.

find out 发现; 使发作
例句：I'll find out the address,and ring you back.
我找到地址后再与你通电话。

4. The ball is filled with 12.5 tons of sodium to reproduce the Earth’s outer core.

fill with （使） 充[挤]满; （某种情感等） 使满怀
例句：His mind began to fill with dreadful thoughts,
他心里逐渐充满种种可怕的念头。

5. A 1-meter-wide inner non-magnetic steel ball is used to represent Earth’s solid iron core.

be used to 习惯于，适用于
例句：She is used to hard work.
她习惯于艰苦工作。