根据句意及首字母完成句子。

小题1:Don’t forget to buy a s       before you post the letter.

小题2:The old man lives in the house by himself , so he feels very l           .

小题3:You must t       away the waste . It’s very dirty.

小题4:Mother often w         me to practice playing the guitar harder.

小题5:The students often have a f         exam at the end of the term.

当圆锥滚子轴承在正常的环境下运行时，对轴承造成主要伤害的是滚动接触表面的最终疲劳。