【正确答案】 He has lost his passport again, which is especially annoying, for he is to attend a conference in Paris tomorrow. // He has lost his passport again. That is especially annoying, for he is to attend a conference in Paris tomorrow.

【答案解析】 本题考查破句的修改。可以将这两个句子合并为一个句子，把which前的句号改为逗号，使“which is especially annoying”作非限制性定语从句，修饰前面的整句话；也可以直接把which改为指示代词that，指代前面所描述的情况。