[求助]关于时态的判断

kaolaxiong

请问：主句主语中有表示一段时间的状语，主句用过去时还是完成时？
《白勇语法全解》时态部分对两道题的解释好像矛盾啊

7（大全319）

1.       
From 1982 to 1987 sales of
new small boats increased between five and ten percent annually.

    

(A) From 1982 to
1987 sales of new small boats increased between five and ten percent annually.

    

(B) Five to ten
percent is the annual increase in sales of new small boats in the years 1982 to
1987.

    

(C) Sales of new
small boats have increased annually five and ten percent in the years 1982 to
1987.

    

(D) Annually an
increase of five to ten percent has occurred between 1982 and 1987 in the sales of new small boats.（A）

    

(E) Occurring from
1982 to 1987 was an annual increase of five and ten percent in the sales of new
small boats.

    
解释说1982-1987，推出一定要用一般过去时

14（大全101）

    

Although the Supreme
Court ruled as long ago as 1880 that Blacks could not be excluded outright from
jury service, nearly a century of case-by-case adjudication has been
necessary to develop and enforce the principle that all juries must be drawn
from “a fair cross section of the community.”

    

(A)
has been necessary to develop and enforce the principle that all juries must be

    

(B)
was necessary for developing and enforcing the principle of all juries being

    

(C)
was to be necessary in developing and enforcing the principle of all juries to
be

    

(D)
is necessary to develop and enforce the principle that all juries must be（A）

    

(E)
will be necessary for developing and enforcing the principle of all juries
being

    
这里解释说a century是一段时间，所以用现在完成时更好……

可前面那道题1982-1987，也是一段时间啊……

很迷惑……
诚请大侠指点！

everann

第2句话是第2个世纪以来case-by-case的adjudication，一个持续改进的过程，并且与现在接壤。