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tipping point临界点
例句：The tipping point seems to be about 30 per cent.
能产生重大变化的数字似乎是30%左右。
2.They are stepping up the sanitation at latrines.
step up(使)增加, (使)加快速度
例句：The girl stepped up to school.
女孩子加快步伐去上学。
He has stepped up into the management of the firm.
他已升入公司的管理部门。
3.They are also having trucks on standby in order to take people throughout the night to hospitals if they feel sick.
on standby待命状态，整装待发
例句：The emergency services were put on standby after a bomb warning.
接到炸弹警报后，各紧急救助部门进入待命状态。
