account for说明(原因等)，解释，还有“占...比例”等的意思。请看：
1. account for说明(原因等)，解释（某种事实或情况）
Can you account for your absence yesterday?
你能解释一下你昨天为什么缺席吗 ?
You need to account for why you were late.
你需要解释一下为什么迟到了。
Of course, no index can account for everything(2013年12月六级)
当然，没有哪个指标可以解释所有事情。
Now, the gene they discovered today doesn't account for all those cases.
不过，他们现在发现的基因无法解释所有的病例。
How do you account for the company's alarmingly high staff turnover?...
你怎么解释这家公司高得令人忧虑的人员流动率？
Ministers should be called to account for their actions.
部长们应该对他们的行为作出解释。
How do you account for the company's alarmingly high staff turnover?
你怎么解释这家公司高得令人忧虑的人员流动率？
Can you account for why this project is delayed?
你能为我解释一下为什么这个项目会延期吗?
They must account for the mistakes they made and explain the reasons.
他们必须为所犯的错误负责并说明原因。
We can’t account for this strange phenomenon.
我们不能解释这个奇怪的现象。
You need to account for the missing funds in your report.
你需要在报告中解释缺失的资金。
He had to account for his mistakes.
他必须对他的错误作出解释。
2. account for（数量或比例上）占
Computers account for 5% of the country's commercial electricity consumption.
计算机占去该国商业用电的5%。
Exports account for a large part of the country's economy.
出口占据了该国经济的很大一部分。
The minority nationalities account for six per cent of the population.
少数民族占人口的百分之六。
Together they account for less than five per cent of the population
他们总共占不到总人口的5%。
The social services account for a substantial part of public spending.
社会福利事业占了一大部分的公共支出。
Last year Oxbridge graduates accounted for 41% of entrants to the civil service's fast stream to promotion.
去年加入快速晋职队伍的新公务员中，牛津和剑桥大学的毕业生占了41%。
Private sponsorships only accounted for a third of all arts funding last year.
个人赞助只占去年所有艺术基金的三分之一。
Catering may now account for close on a quarter of pub turnover.
承办酒席现在可能占酒吧营业额的近1/4。
Sales revenue accounts for 60% of the company's total revenue.
销售收入占公司总营收的60%。
In 2007, Nokia accounted for more than 40% of mobile phone sales worldwide.
2007年,诺基亚在全球手机销售中的份额超过40%。六级真题- 2015年 12月
3. account for 对（行动、政策等）负有责任；对……作出解释或说明
The President and the President alone must account for his government's reforms.
总统必须为他的政府改革负责，而且是负全责。
The manager was asked to account for the mistake.
经理被要求为那个错误负责。
She had to account for all the missing money.
她必须对所有失踪的钱负责。
4. account for将（钱款）列入预算
The really heavy redundancy costs have been accounted for.
非常庞大的裁员开支已被列入预算。
We have to account for every penny we spend on business trips.
我们出公差所用的每一分钱都得报清楚。
5. account for杀死；消灭；打败
In the first ten days of May our squadron accounted for at least seven enemy aircraft.
5月的头10天里我们中队至少报销了7架敌机。
In the final they accounted for Brentford by three goals to two.
决赛时他们以3比2击败了布伦特福德队。
6. account for查明
He said only 200 of the train's 600 passengers had been accounted for.
他说火车上的600名乘客中仅有200名乘客的信息得已查明。
7. account for是……的原因
His good manners account for his popularity.
他的好的礼节是他受欢迎的原因。
8. account for 排除、考虑（因素、情况）
The study accounted for various factors that could influence the outcome.
这项研究考虑了可能影响结果的各种因素。
We need to account for inflation when calculating the final costs.
在计算最终成本时，我们需要考虑通货膨胀因素。