Tired, Jim was fast asleep with his back ____ a big tree

Would you please ______ my baby when I am cooking.

The village is ________ on all sides by green mountains, which is rich in natural resources.[ ]

Management theories are ____ but the methodof doing business is different

填入下面文段空白处的词语，最恰当的一组是 研究先秦诸子著作文本，( ① )研究先秦诸子著作目录版本，( ② )要探讨先秦诸子著作文本和先秦诸子思想之间的复杂关系。先秦诸子著作文本在文体形式上，( ③ )有“语录体”和“对话体”，( ④ )有“论文体”和“春秋体”。同时，先秦诸子著作文本还有“经”“说”“解”的差异，这就( ⑤ )是文体形式的问题了，( ⑥ )涉及文本作者、写作年代、写作地点及其各自表达的不同思想内容。