Q18:

Antarctica receives more solar radiation than does any other place on Earth, yet the temperatures are so cold and the ice cap is reflective, so that little polar ice melts during the summer; otherwise, the water levels of the oceans would rise 250 feet and engulf most of the world’s great cities.

A. is reflective, so that little polar ice melts during the summer; otherwise,

B. is so reflective that little of the polar ice melts during the summer; were it to do so,

C. so reflective that little polar ice melts during the summer, or else

D. reflective, so that little of the polar ice melts during the summer, or

E. reflects so that little of the polar ice melts during the summer; if it did

单从结尾的角度看,abcd的结尾是不是都可以呢

不行.were it do so 是:if it were to do so虚拟语气的省略形式.这里要用虚拟语气表达最好.