OG13的原题：

13. State officials report that soaring rates of liability insurance have risen to force cutbacks in the operations of everything from local governments and school districts to day-care centers and recreational facilities. (C)
(A) rates of liability insurance have risen to force
(B) rates of liability insurance are a force for
(C) rates for liability insurance are forcing
(D) rises in liability insurance rates are forcing
(E) liability insurance rates have risen to force

Answer to Question 13
In choices A and B, rates of is incorrect; when rates means "prices charged," it should be followed by for. Also in B, are a force for does not accurately convey the meaning that the soaring rates are actually forcing cutbacks in the present. In A and E, it is redundant to say that soaring rates have risen. Similarly, the word rises makes D redundant. C, the best choice, is idiomatic and concise, and it correctly uses the progressive verb form are forcing to indicate an ongoing situation.

[rate of 和 rate for(及同类词)的区别总结]

for常被翻译成“为”，但也可表示“的”，如“reason for sth. is …”。

但在表示价格，费用，成本，保险金，花销等于钱有关的“的”，何时用for何时用of需要因词而定。以下是总结和OG例句。

1) rate

OG13中说的很清楚，当rate表示“price charged”时，后面只能跟for. 当表示“率”时常跟of.

a) States officials report that soaring rates for liability insurance are forcing…

b) rate of growth, rate of increase, rate of reduction, death rate of enlisted man, the rate of cell elongation, rate of loss, rate of inflation….

2) price, cost后面即可跟for又可跟of.

a) … the cost for their children’s college education.

b) … thus reducing costs for chemicals, …

c) The contractual price will be greatly affected by the cost of materials used for the products.

d) As a direct result, the cost of those products to the buyers, …

e) Prices for palm fruit fell between 1980 and 1984 …

f) If more lawyers advertise lower prices for specific services, …

g) Projected increases in the price of gasoline will increase the cost of taking a private vehicle into the city.

h) The price of insurance increased more rapidly than the rate of inflation between 1960 and 1990.

3) 如rate在OG13中那样，premium, fare和 fee 都表示“price charged”所以后面跟for。但后面跟同位语金额时用of.

a) … the fee for transporting a radio from Country Q to Country Y…

b) A certain mayor has proposed a fee of five dollars per day

c) Fares for all bus routes in LACE>GreenvilleLACE> have risen …

d) legal advertisements must specify fees for specific services …

e) Premiums for the policy must be low enough …

f) Unlike the premiums for auto insurance, the premiums for personal property coverage

大家可以继续讨论！

我认为，关键在于for和of本身的区别：for表示对应某物而产生的，如：rate

for increase表示增长所需的费用，而rate of increase就表示增长的速度。

这里并不是因为rate的意思不同导致使用不同介词，而是因为使用了不同的介

词使得rate的意思产生不同。所以反过来说当需要表达不同的意思的时候，就

要选择不同的介词使得中心词产生相应的意思。

thanks !!!!!