英语翻译并翻译一下.It's easy to think to oneself than one's emotions

英语翻译
并翻译一下.
It's easy to think to oneself than one's emotions used to be more active than they are ,and one's mind more keen .If this is true it should be forgotten ,and if it is forgotten it will be probably be not true .
书上译文是：人们很容易认为自己的感情不如以前活跃，思维不如以前敏捷，如果这是真的，那就应当忘记它，忘记也许就不会成为现实。
不明白那两个than...than...是怎么回事。比如，主语、谓语、宾语....