I just noted the difference between Ed's sentence and the Chinese student's
original sentence.  I'd recommend starting over.

Sara
At 01:51 PM 09/22/1999 -0400, you wrote:
>I am tempted to  agree with Edith, but I think the answer should be (D),
"what":
>
>Electricity is to agriculture what blood is to the body.
>
>"Like" or "as" would establish a simple comparison:
>   "A" is to "B" as (like) "X" is to "Y."
>
>The use of "what," however, establishes a further identity between "A" and
"X" ¯ in this case, they are equal in the sense of being sources of energy.
>
>
>
>
>>>> "Wollin, Edith" <[log in to unmask]> 09/22 1:32 PM >>>
>They gave you a wrong answer--the answer is A.  Like or As are possible in
>the blank; the others are not.  A comparison is being made
>
>> ----------
>> From:         xql[SMTP:[log in to unmask]] 
>> Reply To:     Assembly for the Teaching of English Grammar
>> Sent:         Wednesday, September 22, 1999 6:22 AM
>> To:   [log in to unmask] 
>>
>> Hello,everyone.
>> I'm a chinese student.I came across a question as follows:
>>
>> Electricity is to the agriculture _____ blood is to the body.
>> A)like
>> B)that
>> C)which
>> D)what
>>
>>
>> The answer is C),and I don't know why.Is B) right?
>> Thanks .
>>
>
>
Sara Garnes
Associate Professor of English
Ohio State University
e-mail: [log in to unmask]