地球上最大的生态系统是（　　）

看图把句子补充完整。

蘑菇是小白兔的____。

    Hello, everyone! I am your1 today. First, I'd like to 2 you something about London before we3London is a very big city of England. The people here are friendly. They are always 4 to tell visitors something about the city.

    London is a busy place. People_5hard. They are very 6 all the time (一直). London is also a very beautiful city. It has a lot of parks and gardens (花园). When you are in London, you can7the British Museum. It can tell you a lot of 8stories. You may also visit9 place. It is the River Thames. It's long and wide. There are many boats on the river.

    May you have a good10！We will get to London in two hours. Now let's have a guessing game.

有的同学认为“罪犯都是法院、检察院去判，做事都是有权的说了算，所以权利都在当官的手里，并不在我们人民手里”；也有的同学认为“我们还小，国家事务与我们无关”。请你结合所学知识对以上观点进行评析。