能够把自然地理环境中有机界和无机界联系起来的是

阅读短文，判断下列句子是否正确。
    Ann went to Qingdao with her friends on her holiday. They went there by train. They went to the beautiful beach. The weather was sunny and hot. So they had great fun playing in the water.They ate lots of fresh fish for lunch. In the afternoon, they rode bikes. Jack fell off his bike and hurt his leg. So Jack stayed at the hotel and watched TV. On the second day, Ann took many pictures of the sea. And she bought some gifts for her parents. Anyway, they had a good time.

____÷4＝____，表示____里面有____个____。

下列二次根式中与$\sqrt{2}$是同类二次根式的是（    ）

浙江杭州市的武女士带着上八年级的女儿在回家的路上，遭遇歹徒持刀抢劫，母女用唇语暗号成功脱险。这一案例告诉我们（    ）