下面是制作酸奶的几个步骤：①牛奶煮沸后冷却；②放到常温环境中 1 天；③在牛奶中加入少量的含乳酸菌的酸奶；④密封瓶口。正确的操作顺序是（   ）

    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).

—I'd love to travel all _____ the world.