An English gent leman always takes an umbrella and wears a hat. Why? In England, it rains often. The rain comes at any time, so an umbrella is necessary (必要的) in people's life. English gentlemen love to take a long black umbrella. It is useful when the rain comes. And it is also a style. The hat plays an important part in their life too. If two men meet in the street,  they take off (脱掉)  their hats to show their respect (尊重) to each other. If a man visits his friend, he takes off his hat frst when he gets into the room. If he goes to a party, he can only put the hat on his chair, but not on the table. You don't have the two things, but you can still (仍然) be a gentleman. Always be nice to others and be ready to help others. Show your respect and love to old people, women and children. Never shout. Never lose your temper (发脾气).

2cos60°的值是（　　）

下列关于海陆分布的说法，正确的有     (    )
①两极周围均是陆地②陆地主要集中在北半球③东、西半球海陆分布比较均匀
④除了北冰洋以外，其他大洋均跨南、北半球

某化学反应中产物的总能量为60kJ，如果该反应是放热反应，那么反应物总能量可能是（　　）