Dear vp_helper,

After looking at the explaining of the key, this question still puzzled me.

"Syivia:some psychologists attribute complex reasoning to reptiles,claiming that simple stimulus-response explanations of some reptiles' behaviors,such as food gathering,cannot account for the complexity of such behavior.Bust since experiments show that reptiles are incapable of making major alterations in their behavior,for example,when faced wtih significant changes in their environment,thes animals must be incapable of complex reasoning.

(A) Animals could make major changes in their behavior only if they were capable of complex reasoning.

(B) Simple stimuls-response explanations can in principle account for all reptile behaviors.

(C) Reptile behavior appears more complex inthe field than laboratory experiments reveal it to be.

(D) If reptiles were capable of complex reasoning,they would sometimes be able to make major changes in their behavior.

(E) Complex reasoning and responses to stimuli cannot both contribute to the same behavior."

I thought the key D maybe wrong because it can infer that if reptiles were capable of complex reasoning,they would sometimes be not able to make major changes in their behavior according to the content of D.

I thought the key A maybe right.
Longman dictionary defined that "only if used when sth will happen if sth else happens first but will definitely not happen if the first thing does not."
Based on A,it can said animals could not make major changes in their behavior if they were not capable of complex reasoning.In other words,if animals are incapable of making major alterations in their behavior,the only reason is the animals incapable of complex reasoning.

Did I miss something? Thanks a lot

I'm afraid I'm not familiar with Longman Dictionary...
However, here's the case on this problem.
The author claims that we can conclude that animals aren't capable of complex reasoning because they aren't able to make big behaviorsl changes when faced with big environmental changes. If we can state this, then we can state that the other side must be assumed here -- if they were capable of complex reasoning, then they would at least sometimes be able to make big behavioral changes when faced with environmental changes.
The problem with the other option is the "only" part of it -- we don't know that they would be able to make big changes ONLY if capable of complex reasoning. There *could* be other ways for them to make big changes - e.g. training, physical adjustments of some sort, etc...

DOes that help some?

Veritas Help

Thanks for your excellent instructing. I understand it finally.