When you are in England, you must be very careful in the streets because the traffic drives on the left. Before you cross a street, you must look to the right first and then left. If the traffic lights are red, the traffic must stop. Then the people on foot can cross the road.
    If the traffic lights are green, the traffic can go. People on foot mustn't cross. In the morning and in the evening when people go to or come from work, the streets are very busy. Traffic is most dangerous then.
    When you go by bus in England, you have to be careful, too. Always remember the traffic moves on the left. So you must be careful. Have a look first or you will go the wrong way.
   In many English cities, there are big buses with two floors. You can sit on the second floor. From there you can see the city very clearly. It's very interesting.

铝在工业和日常生活中应用广泛．请回答：

（1）铝元素的含量居地壳中所有元素的第____ 位．将铝块拉成细丝、压成薄片是利用铝的____ 性．

（2）元素的化学性质与原子的最外层电子数有密切关系．右图为铝原子的结构示意图，铝原子在化学反应中容易____（填“得到”或“失去”）电子．

（3）铝在空气中与氧气反应，其表面生成一层致密的氧化物薄膜，从而阻止铝进一步氧化，因此铝具有很好的抗腐蚀性能．写出铝与氧气反应的化学方程式：____ ．

（4）冰晶石在工业制取金属铝的过程中起着重要的作用．硫酸铝和氟化钠（NaF）在熔融条件下反应生成冰晶石（Na₃AlF₆），同时得到硫酸钠，写出此反应的化学方程式____ 　．

权利与义务是相对立的，履行了义务，就不能享受权利。（     ）