问题补充：
It is already well understood causes the global warming.
A. what
B. when
C. that
D. how
答案：
A. what
B. when
C. that
D. how
解析：可联系答.案.网客服索取。
如果觉得《It is already well understood causes the global warming.A. whatB. whenC. thatD. how》对你有帮助，请点赞、收藏，并留下你的观点哦！
