囧哥做语法37

囧囧哥UID：3408678

Genetic engineering sometimes entails plant or animal genes' getting spliced into other species' DNA, either to improve crop yields or for warding off insects or disease.
A plant or animal genes' getting spliced into other species' DNA, either to improve crop yields or for warding off
B plant or animal genes that get spliced into the DNA of other species,either for improving crop yields or the warding off of
C the splicing of plant or animal genes into other species' DNA, to either improve crop yields or to ward off
D splicing plant or animal genes into the DNA of other species, either to improve crop yields or to ward off
E splicing of plant or animal genes into the DNA of other species, for either the improvement of crop yields or to ward off

句子结构：
Genetic engineering entails plants or animal genes' getting spliced into..., either ...or...
根据either or的平行结构排除ABCE 所以选D