《岳阳楼记》是我国北宋文学家______的散文名篇。 ( )
A．欧阳修
B．柳宗元
C．韩愈
D．范仲淹
参考答案：D
变异最易出现在
A．迟缓期
B．对数期
C．稳定期
D．衰亡期
E．以上均可
Knowledge and learning are important if we want to be successful, but they may also ______ our thinking.
A．direct
B．limit
C．change
D．improve
