①认识的不断完善决定着实践的不断深化

②认识的发展是一个不断推翻已有认识的过程

③新的认识工具和技术手段的出现推动着认识的发展

④认识受认识对象本质和属性暴露程度的制约

①良种畜群迅速扩大，加速了育种工作和品种改良；

②在世界范围内，胚胎移植不受时间和地域的限制，大量节省了购买种畜的费用；

③利用胚胎冷冻保存技术，建立胚胎库，保存品种资源和濒危物种；

④在肉用家畜的生产中，一次给受体移入多个胚胎，可增加双胎和多胎的比例．

阅读理解
　    Many people have to work on the weekend. Some people do not mind. Others think it is terrible.
　　One man thinks that working on the weekend can be dangerous. He is Graham Coates. Mr Coates works in an office in Brighton, England.
　　On Saturday, May 24, 1986, he went to the office to do some work. When he got on the lift(电梯), it stopped between floors. Mr Coates could not get out of the lift. He started to shout, but no one heard him. Then Mr. Coats remembered that it was a holiday in England. No one was going to come to work until Tuesday.
　　There was nothing for him to do. He had to wait until one of his workmates came to work and found him. With nothing to eat or drink, Mr Coats ended up sleeping for most of the day.
　　Now Mr. Coates says, "I only use lifts if they have telephones in them."