If its distance from the eye is halved, its apparent size is doubled . 同一物体，与眼的距离减半，相对大小就大一倍。
Statistics suggest that the population of this country will double in ten years' time . 统计显示，这个国家人口在十年内将增加一倍。
A 15-minute dose of red light can double the previous respiration rate of the plants . 照射15分钟红光可使植物原来的呼吸速率提高一倍。
The united states air force was going to be doubled, or perhaps trebled, in the next six months . 在未来的六个月中，美国将把它的空军增加一倍或两倍。
This demonstrates that adding another element to the whole set doubles the number of subsets . 这说明在一个集中加入一个新元素，其子集的总数扩大一倍。
On january 16, 1979, the shah left town, within a few weeks, the price of gas doubled . 1979年1月16日，伊郎国王出走了。几个星期后，汽油价格上涨了一倍。
Dot aged about fourteen, but looking twice as developed as phyl who was five years her elder . 黛特虽然不过十四岁左右，比菲儿小五岁，可是长得比她丰满一倍。
Purkinje fibers are driven ("over driven") by the sinus node at twice their intrinsic rate . 浦氏纤维是被较其本身频率约高一倍的窦房结所驱动（“超速驱动”）。
The man who gave his vote for the longest time, on having his judgment disputed, grew stubborn, and doubled his time . 那主张最长时间的人因为受了批驳而更加坚持，又把时间放长了一倍。
By the eve of the first world war, european investments in the united states, direct and indirect, had more than doubled . 到第一次世界大战前夕，欧洲人在美国的直接和间接投资增加一倍以上。
