关于that后面句子的问题

小王子L

83. 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

(A) a phenomenon that is explained not just because
of more expensive drugs but by the fact that
doctors are writing
(B) 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
(C) a phenomenon occurring not just because of
drugs that are becoming more expensive but
because of doctors having also written
(D) which occurred not just because drugs are
becoming more expensive but doctors are also
writing
(E) which occurred not just because of more
expensive drugs but because doctors have also written
OG里面说B是正确的。C中drugs that are becoming more expensive 是得，为什么B  a phenomenon that is explained 就对了，那个THAT 不能省略么。我看到很多THAT后面有BE动词的都是awkward，求大牛解释、

yuganmu

我今天也在看这个题 不懂啊· 为什么D不对
(D) which occurred not just because drugs are becoming more expensive but doctors are also writing

wwc008love

(A) a phenomenon that is explained not just because
of more expensive drugs but by the fact that
doctors are writing
看原句的意思，作为同位语解释一个phenomenon..that引导定语从句修饰phenomenon
A错在not....but..不平行
正确选项B  that不省略的原因是  它和原句要表达的意思一致，即that引导定语从句。。
(C) a phenomenon occurring not just because of
drugs that are becoming more expensive but
because of doctors having also written
C我觉得有2个错误。a phenomenon occurring..一直在发生的现象？原句没这个意思
sb having done这个典型的错误形式。。
总之要看原句的意思。。。

kenny1123

这里有转折的意思吗？我怎么感觉药物变贵了和医生开贵的处方是共同引起的这个现象啊？
但是好像有那么一点递进的感觉，就是药物也是一个原因，但是医生的原因是更主要的.

小王子L

这个刚好我知道，其实这个可以分开用的，要看他表达的意思是并列还是转折，如果是并列就要一起用，如果表示的转折用but also就可以，看句子具体的逻辑意思而定。

kenny1123

我也刚好在看这题诶，不是OG里经常说not only but also 要连用的吗？
B选项里只有not just but also 也可以吗？