The waters of the lake were so     that it looked like glass . 

She felt _____ of having asked such a silly question when the audience couldn't help laughing.

 He got completely______ when he saw both Lucy and Lily, who are twin sisters.

Mary is always ready to do some __ work at the local geracomium（敬老院）in her spare time.

It is not socially          for parents to leave children unattended at that age.