问一道语法，11th og 82

82. Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone and varying the electrical properties of underground rocks

(A)  changing the measured strain across a fault zone and varying

(B)  changing measurements of the strain across a fault zone，and varying

(C)  changing the strain as measured across a fault zone，and variations of

(D)  changes in the measured strain across a, fault zone，and variations in

(E)  changes in measurements of the strain across a fault zone，and variations among

og的解释是这样：The first two signs are parallel．The third and fourth warning signs resemble tilling in the—ing form，but they are not parallel because they are used as verbs rather than as nouns：changing．．．the strain；varying．．．the properties．To make the latter two signs parallel，nouns must replace verbs：changes in．．variations in．

怎么才能识别这种表面的平行呢？？

fluctuations和tilting都是名词结构，changing ＋n.（一个动作）的话在这里就是分词做状语了．

看到有逗号敏感一点，如果前后两个成分结构一致且中间没有and, 那么后面就要考虑结构和前面一致（fluctuations，tilting和changes 都是名词结构）还有最后一项前加and了．

谢谢