问题补充：
We know that the Black Sea, one thousand years ago, was a fresh water lake about and unconnected with the Mediterranean.
A. its two thirds present size
B. two-thirds size of the present
C. its two-thirds of the present size
D. two- thirds its present size
答案：
A. its two thirds present size
B. two-thirds size of the present
C. its two-thirds of the present size
(答案→)D. two- thirds its present size
解析：考查倍数和分数的表达问题。“某物以前的大小/长度/宽度/深度是现在的几倍/几分之几”的表达法：基数词+times/分数 its present size/length/width/depth”，注意，这个结构是没有of的。选D。
