Now，an Internet game became more and more popular. People can “farm” on a piece of “land” and “grow”，“sell”(卖)“vegetables”, “flowers” and “fruits” on the Internet. They can make some e-money and buy “houses”.
What do people think of this game? Here are, some ideas.
Harold：I think they don'like the real world and it is hard for them to face the real world.
Allan：Having fun together is the most exciting thing about it.
Laura：People are looking forward to the life in the village. It can help them understand the real world.
Ivy：It's just waste(浪费) of time. People will not focus on(专注于)their work or study if they spend too much time on it.

“如果你有一个苹果，我有一个苹果，彼此交换，我们每个人仍只有一个苹果；如果你有一种思想，我有一种思想，彼此交换，我们每个人就有了两种思想。”萧伯纳的这句名言告诉我们应（  ）

已知 |x-1|+|y+1|=0 ，求下列各式的值：

一个梯形的面积是24平方分米，如果高是6分米，那么上底与下底的和是____分米．