小明的学习成绩一直名列前茅，许多同学暗暗把他当成竞争对手，而他却总是耐心地为同学讲解练习题，有人说他这样会被别人超过，但他认为“帮助别人也是提升自我”。这表明小明（   ）

动物在生物圈中的作用有（  ）

①维持生态平衡

②促进生态系统的物质循环

③帮助植物传粉、传播种子．

根据句子意思及首字目提示写出单词的正确形式。
Talking about others' p____  life is not polite.           
I have r____ a special present from my pen pal in Australia.  
Last month, I spent a w____  vacation in the countryside.
I have two pens, but n____  of them works well.
Go down this street and turn left at the second t____ lights.
I'm c____ that he will win first prize in the competition.

Some singers sing songs to r____ money for the poor children.

Rose is so c____  that there is no mistake in her homework.

如图，等腰直角三角形ABC的直角边AB的长为6cm，将△ABC绕点A逆时针旋转15°后得到△AB′C′，AC与B′C′相交于点H，则图中△AHC′的面积等于（　　）