人的视觉形成的部位是（）

下列各句中，成语使用正确的一项是（    ）

阅读诗歌回答后面小题。
                                                                                                              跌 倒
                                                                                                              牧 也
                                                                                                       风，跌倒了
                                                                                                      才有了美丽的落叶
                                                                                                      云，跌倒了
                                                                                                      才有了滋润大地的雨水
                                                                                                       所以
                                                                                                       我们不再害怕跌倒
                                                                                                       让我们在跌倒时
                                                                                                       用最美丽的姿势
                                                                                                        站起来

鳃是水生动物适应水中生活的一种重要的呼吸器官，下列动物用鳃进行呼吸的是（　　）　

判断对错

四条边相等的四边形是正方形