1 grave

2 serious

3 severe

4 critical

1 to repeat

2 repetition

3 again

4 re-

5 classifier: layer

1 again

2 once more

3 re-

1 important

2 significant

3 major

1 to take care of oneself

1 each word carries weight

2 a promise must be kept (idiom)

1 lit. not knowing what's important (idiom); no appreciation of the gravity of things

2 naive

3 doesn't know who's who

4 no sense of priorities

1 total defeat of an army (idiom); fig. a complete wipeout

1 lit. the cart in front overturns, a warning to the following cart (idiom); fig. draw lesson from the failure of one's predecessor

2 learn from past mistake

3 once bitten twice shy

1 high merit and worthy prospects (idiom)