2. 用含有增减意义的动词 increase/decrease, climb/fall,go up/decline. . . + by n-fold ", decrease, fall, decline, . . + by/to表示,例如:
a. Per capita living space in this city has increased / enlarged by 1.5 times since 1978. (用 by)
这个城市的人均居住面积自1975年以来扩大了1.5倍。
b. The factory was ordered to cut spindles to one-third. (by two thirds)
这家纺纱厂被责令把纱锭压缩到三分之一。(减少三分之二)
c. During this period the greening area increased two-fold.
这期间绿化面积扩大了一倍。
需要说明的是,在表示增加多少倍,特别是百分之几时,有的用by,有的则不用,在增加/增长百分之几的情况下,不用的例子很多,例如:
a. Bankers Trust New York Chase Manhattan and JP Morgan said those profits could fall 30 to 70 per cent from the third quarter. (不用 by)
—South China Morning Post, Dec. 29,1994
纽约银行家信托大通和JP摩根公司称,这些利润可能比第三季度下降百分之三十到七十。
b. The output of chemical fiber has been increased three times as against 1975. (不用 by)
——《实用英语语法》,第2版,
第102页,张道真著
化学纤维产量比1975年增加了两倍。
c. The United States' unemployment rate dropped 1.3 percentage points during the year.(不用 by)
美国当年的失业率下降了1.3个百分点。
d. Kunming Machine Tool was the best performer of the day, rising 27.5 cents or 13 per cent per share. (不用 by)
—South China Morning Post, Dec. 29, 1994
昆明机床(股票)这天的交易最好,每股上涨27.5美分或者说百分之十三。