问题详情

In the sentence "an area covering 30% of the earth"s land surface is desert, becoming desert, or in danger of becoming desert" , the part of " is desert, becoming desert, or in danger of becoming desert" can be best replaced with____.
A．is becoming desert, has become desert, or will becoming into desert
B．has been desert, is becoming desert, or will become into desert
C．is becoming desert, will become desert, or becomes into desert
D．has been desert, is becoming desert, or will become into desert此题为多项选择题。请帮忙给出正确答案和分析，谢谢！