独立生活教会了我要更小心地花钱。

Living on my own ___taught me to be more careful with money.

丢过一次钥匙的经历教会了我总要留一把备用的。

Losing my keys once ___taught me to always keep a spare.

那次考试不及格让我明白我需要更努力学习。

Failing that test ___taught me that I need to study harder.