萤火虫发光所需的能量来源于细胞____．

回答与草原生态系统相关的问题；

先化简，再求值：

4xy﹣（x²+5xy﹣y²）﹣（x²+3xy﹣2y²），其中x=- $\frac{1}{4}$ ，y=- $\frac{1}{2}$ ．

在参加福建省首届“最美教师”网络投票时，小闽浏览了下列跟帖留言。你认为其中符合活动主旨的是（　　）

①教师是唯一的教育者                  ②教师是教学的绝对权威

③教师应是学生的良师益友          ④尊师重教成为社会风尚

根据括号里的单词提示，完成短文填空。

   Everyone ____ (have) birthday. Ways of celebrating birthday are different.

   In America, parents have a party ____ their birthday kid. The birthday kid can get lots of presents and eat the birthday cake with friends. In Brazil, special candies are ____ (need) for birthday. In England, the birthday kid ____ (lift) up and putdown by his classmates ____ (happy). In Thailand, two tall candies are lighted the night before birthday.

    As we all know, it is getting popular to have cake on birthday in China. But parents usually cook ____ big dinner for the kid on birthday. The birthday kid eats long noodles or eggs. Long noodles mean long life and eggs bring good luck.

    People in different ____ (Country) have different ways to celebrate birthday. It is important for us ____ (celebrate) birthday. Everyone grows one year ____ (old) after his or her birthday. Relatives and friends feel ____ (happy) for his or her growing up.