阅读下面一首诗歌，完成下列小题。

金陵城西楼月下吟

李 白

金陵夜寂凉风发，独上高楼望吴越。

白云映水摇空城，白露垂珠滴秋月。

月下沉吟久不归，古来相接眼中稀。

解道“澄江净如练”，令人长忆谢玄晖^①。

【注】①谢玄晖：名谢朓，南齐著名诗人。

    We are learning English, but how can we learn English well? A student can know a lot about English, but maybe he can not speak English.
If you want to know how to swim, you must get into the river. And if you want to be a football player, you must play football. So , you see, you can learn English only by using it. You listen to your teacher carefully in class. You must read your lessons every day. You must speak English to your English teacher and classmates and also you must write in English. Then one day, you may find your English very good.

已知化合物A（）与立方烷（）的分子结构相似，如下图：

则的二氯代物的同分异构体数目为（   ）

对某澄清透明溶液进行离子检验，实验结果如下，其中明显错误的是（　　）

草履虫的呼吸是通过（   ）进行的．