When spring comes, they began their long journey north.
出自-2014年6月听力原文
In the 1990s, many economists began to look at chaos theory as a way of providing models for forecasting.
出自-2013年6月听力原文
As a young man, he began walking over tens of thousands of miles during his lifetime, through the south to Florida, the west to California and north to Alaska, where readers are taken a long and particularly hair-raising adventure on a large mass of floating ice
出自-2013年6月听力原文