1. This is your case, it's entirely up to you, this is just friendly advice.
這案子你接了 完全歸你管 只是要給你提個善意的醒

由...決定

eg:I give you blessings; Happiness is up to you.
我給予你祝福，快樂幸福是你自己的選擇。

2. He was killed by a single blow to the back from a blunt instrument.
他是腦后遭鈍器襲擊 一擊斃命的

鈍的，不鋒利的

eg:Too much alcohol made the young driver's sense blunt.
大量喝酒使得那個年輕 司機感覺遲鈍。

3. He's trying to be clever. It's overconfidence.
自作聰明 自信心膨脹

自負，過分自信

eg:Overconfidence in oneself is the first step to fail.
過度自信是走向失敗的第一步。

4. Low self-esteem, tiny IQ and a limited life expectancy.
自信不足 智商低下 胸無大志

期望，期待

eg:For most Americans, life expectancy continues merrily to rise.
對于大多數(shù)美國人來講，壽命預期持續(xù)喜增。