中国的陆地面积约为9 600 000km2,把9 600 000用科学记数法表示为____ .
As a new graduate,he doesn't know ________ it takes to start a business here. ( )
治理黄河的关键是:( )
观察下列一组漫画,根据所学知识,回答下列问题。
下列各式中,y是x的二次函数的是( )