gwd-7-39

Q39:

In 2000, a mere two dozen products accounted for half the increase in
spending on prescription drugs, a phenomenon that is
explained not just because of more expensive drugs but by the fact that doctors
are writing many more prescriptions for higher-cost drugs.

1. a phenomenon that is explained not just because of more
        expensive drugs but by the fact that doctors are writing
2. a phenomenon that is explained not just by the fact that drugs
        are becoming more expensive but also by the fact that doctors are writing
3. a phenomenon occurring not just because of drugs that are
        becoming more expensive but because of doctors having also written
4. which occurred not just because drugs are becoming more
        expensive but doctors are also writing
5. which occurred not just because of more expensive drugs but
        because doctors have also written

not just=not only, just在这里相当于only

C中phenomenon 同occurring 意思重复，同时两个because后面要跟完整的句子， not only because drugs are becoming more expensive but because doctors are writing,这样才能把意思说清楚，表示原因是两件事情，而不是两样东西。如果换用两个because of的短语，会发生意思重点错位，让人误以为原因是drugs和doctors 两样东西而不是两件事情。