In America, presidential elections are held every four years.
美国每四年举行一次总统选举。
Many Irish people went over to America during the famine.
许多爱尔兰人在饥荒时期迁徙到美国。
South America separated from Africa 200 million years ago.
2亿年前南美洲和非洲分离。
South America and Africa separated 200 million years ago.
南美洲和非洲于2亿年前分离。
The proportion of small cars on America's roads is increasing.
美国公路上小汽车的比例在逐渐增加。