6. Damaged nerves in the spinal cord do not regenerate
themselves naturally, nor even under the spur of
nerve-growth stimulants. The reason, recently dis-
covered, is the presence of nerve-growth inhibitors
in the spinal cord. Antibodies that deactivate those
inhibitors have now been developed. Clearly, then,
nerve repair will be a standard medical procedure in
the foreseeable future.
Which of the following, if true, casts the most serious
doubt on the accuracy of the prediction above?
(A) Prevention of the regeneration of damaged
nerves is merely a by-product of the main
function in the human body of the substances
inhibiting nerve growth.
(B) Certain nerve-growth stimulants have similar
chemical structures to those of the antibodies
against nerve-growth inhibitors.
(C) Nerves in the brain are similar to nerves in the
spinal cord in their inability to regenerate
themselves naturally.
(D) Researchers have been able to stimulate the
growth of nerves not located in the spinal cord
by using only nerve-growth stimulants.
(E) Deactivating the substances inhibiting nerve
growth for an extended period would require a
steady supply of antibodies.
The answer is A.
C, D, E is definitely wrong.
But I think B is tricky.
SINCE B SAYS,
Certain nerve-growth stimulants have similar chemical structures to those of the antibodies against nerve-growth inhibitors.
AND WE KNOW THAT 药剂的化学结构相似功能作用相似，
THAT MEANS SO CALLED "nerve-growth stimulants" FUNCTION AS "nerve-growth inhibitors".
I think you misunderstanding what B means. B just tells that their chemical structures are similar rather than their functions. Similar structure doesn't mean similar function.
The choice of B is designed to misguide you.
BCertain nerve-growth stimulants) ( those of the antibodies against nerve-growth inhibitors).
After analyzing the sentence, its meaning is clear.
Certain nerve-growth stimulants) 