Err on the side of sth宁愿稍微过一点to show slightly too much rather than too little of a quality

When I am marking exam papers, I always try to err on the side of generosity.
改考卷打分时,我宁肯宽一点.
I thought it was better to err on the side of caution(= to be too careful rather than take a risk).
我认为宁可过于谨慎也不要冒风险.

set your heart/mind on sth,或者是on doing sth.意思就是一心想要某物(或做某事),立志要
when she was a small girl, her heart was set on a horse of her own.
她还是个小女孩时就特别想要一匹属于自己的马.

He set his mind on becoming a doctor.
他立志要成为一名医生.

I have my heart set on a new guitar.
我一心想要一把新吉他.