一、倍数增减的表示法
1) is 2.5 times greater than Force N2
(考点：倍数 + 形容词/副词比较级 + than)
2) reacts three times as fast as the other one
(考点：倍数 + as + 形容词/副词 + as)
3) is 49 times the size of the moon
(考点：倍数 + 名词)
4) wants to raise the rent by a third
(考点：动词 + by + 数词/百分比/倍数)
5) plan to double their investment
(考点：double + 名词)