要变换形式。每词限用一次

    Chicago is a famous city in the US. If you have a(n) ____to go to the US, it is a good idea ____Chicago.

    In the US, Chicago is the third ____city. It is home to people from all over the world. People move to Chicago from ____ places to live with their families or friends. They come to this city by train, plane or ship.

    The centre of Chicago is ____The Loop. You can see many tall ____ here, even some of the tallest in the world. As you travel away from The Loop, you will find there are places of different ____ cultures (文化l). But you can't travel east out of The Loop ____of Lake Michigan.

    When you travel south of The Loop, you will find ____ like Chinatown. There, people from 'China celebrate many festivals as people in their home town do. They also celebrate the holidays of the US.

    Remember to take many ____ with you when you go to Chicago. Why? Because Chicago is called the Windy City.

如图，AB是⊙O的一条弦，点C是⊙O上一动点，且∠ACB=30°，点E、F分别是AC、BC的中点，直线EF与⊙O交于G、H两点，若⊙O的半径为9，则GE+FH的最大值为．

2013年第一季度，泰州市共完成工业投资22300000000元，22300000000这个数可用科学记数法表示为____．

关于浩瀚的宇宙，以下说法中错误的是（  ）。