when David is twice as old as he is now he will be four times as old as his daughter Jane will be in five years time.
问题描述：
when David is twice as old as he is now he will be four times as old as his daughter Jane will be in five years time.
答
David的年纪是他现在的两倍大，现在，他的年纪是他女儿的四倍大，Jane将是五倍那么大
答
当戴维的岁数是他现在岁数的两倍时，他的岁数将会是他女儿简五年后的岁数的四倍。
答
当大卫的年龄增长到现在的两倍时,他的年龄会是那时候他女儿简的年龄的四倍
答
假设jane今年X岁，她爸爸David今年Y岁的话，这句话的意思就是：4（X+5）=2Y
中文意思即：当David两倍于现在年龄的时候，他将是他女儿五年以后年纪的四倍。