求问各位众神一个关于平行的问题

Molliez

693. Discussion of greenhouse effects have usualy had as a focus the possibility of Earth growing warmer and to what extent it might, but climatologists have indicated all along that precipitation, storminess, and temperature extremes are likely to have the greatest impact on people.
A. Discussion of greenhouse effects have usually had as a focus the possibility of Earth growing warmer and to what extent it might,
B. Discussion of greenhouse effects has usually had as its focus whether Earth would get warmer and what the extent would be,
C. Discussion of greenhouse effects has usually focused on whether Earth would grow wamer and to what extent,
D. The discussion of greenhouse effects have usually focused on the possibility of Earth getting warmer and to what extent it might,
E. The discussion of greenhouse effects has usually focused on whether Earth would grow warmer and the extent that is,

想问一下为什么c选项是平行的。。。。whether Earth would grow wamer and to what extent

Fiona09

https://forum.chasedream.com/thread-1166448-1-1.html 传送给LZ

Molliez

Fiona09 发表于 2018-6-5 12:04
https://forum.chasedream.com/thread-1166448-1-1.html 传送给LZ

谢谢小仙女！现在明白鸟