英语翻译这题应该选哪个答案？The most destructive natural disaster,tsunami,

Where does Bush stand in the succession of presidents of US?Where does Bush come in among the presidents of US?What is Bush's order in the list of American presidents 再问： 这题应该选哪个答案？ The most destructive natural disaster, tsunami, came unexpectedly ________ they will always live in peace and comfort。 A。 after B while C where D when 再答： 答案是D when 译文：最具破坏力的自然灾害，海啸，突然降临，此时他们将永远活在静谧和安逸里。 感觉这个选择题有些怪，前半句是过去时，而后面的从句是将来时。时间跨度不好理解。