1）The five year deal obligates [A] the country to buy nine million tons [B] of grain a year [C] ，three million more as [D] the old pact's minimum.
2）The lens of a camera performs the lens of the eye .
[A] in the same function [B] the same function as
[C] the function is the same as [D] and has the same function
3）The elimination of inflation would ensure that the amount of money used in repaying a loan would have as the amount of money borrowed.
[A] as the same value [B] the same value
[C] value as the same [D] the value is the same
4）There are now methods for studying color vision in infants than there once were .
[A] more sophisticated than
[B] much more soph