1.He had made a serious mistake and it was no use trying to minimize its seriousness.
他犯了严重的错误，想漠视其严重性是无济于事的。
2.Though he had made a serious mistake, they did not punish him, out of consideration for his youth.
尽管他犯了严重错误，他们考虑到他还年轻，并没有处罚他。
3.They began to see that they had made a serious mistake.
他们开始认识到自己犯了一个大错误。
4.He made a serious mistake in spelling. Can you point it out?
他犯了一个宽峻的拼写弊端，您能指出去吗？
5.He was so lucky to get away with a fine for such a serious mistake.
他犯了那么严重的错误，却侥幸只交了罚款了事。
6.Indonesian democracy seems to have firmer foundations, but it would be a serious mistake to assume that they are fully built.
印尼的民主根基看似更牢固，但你要认为民主制度已经完全建好，就大错特错了。
7.I never really understand the reason why he made such a serious mistake.
我总不太明白他犯这样一个错误的原因。误的原因。
8.He was going to hand in his exam paper when he found a serious mistake in his writing.
他正要交试卷，就在此时他发现了写作中的一个严重错误。
9.For such a serious mistake he was lucky to get away with a fine.
他犯了那么严重的过失，却侥幸只交罚款了事。
10.I made a serious mistake at the start as my reflexes let me down and I left early.
我在发车时犯了一个严重的错误，条件发射出现失误，过早启动了。