下列关于原子及原子核的说法正确的是（   ）

    There are many different ways to travel to Paris from London. One of the quickest and most popular ways is by train. From Waterloo Railway station, you can travel all the way to Paris. The journey takes about three hours. The train, called the Eurostar, is very modern, and the seats are comfortable.
    You can also travel to France by ship. First, you go to Dover, on the coast (海岸), by bus from London. The bus stops at the Ferry Terminal Seven in Dover. You can buy your tickets there. People who travel by car can drive on to the ferry (渡轮), too.
Another way to travel to Paris is by plane. There are several airports with international flights to Paris and other cities in France. You can travel to London Airport by bus or underground. Some people even go by taxi but this is a very expensive way to travel!

（2015·四川）登上火星是人类的梦想，“嫦娥之父”欧阳自远透露：中国计划于2020年登陆火星。地球和火星公转视为匀速圆周运动，忽略行星自转影响。根据下表，火星和地球相比

①游戏厅   ②公园   ③影剧院   ④贸易集市

尼日利亚人口超过1亿，经济以农矿业为主，石油、铁矿等矿产资源丰富，但能源严重短缺，成品油依赖进口。2010年7月我国和尼日利亚签署协议，在该国最大城市拉各斯（位置见下图）投资80亿美元兴建大型炼油厂。此外，我国还有许多企业参与尼日利亚农业、矿业、电力、铁路等行业建设。