根据句意和汉语注释，写出单词的正确形式。
（1）Our English teacher has offered us some useful ____  (建议). I think it will help us a lot in our English study.
（2）Here are two ____ (音乐会) tickets for you.
（3）Daniel ____ (不愿)  to accept my books ,which made me very sad.
（4）____ (比较) this new TV set with the old one, you will see which is better.

函数$f\left(x\right)=\sqrt{-x^2+2x+3}$的单调递减区间是 （  ）

在地质年代越久远的地层中，成为化石的生物是（　　）