填空题 Mark Twain seemed unhappy in his later years because his wife and 1 had died.

  • 1、
【正确答案】 1、three of his children。    
【答案解析】[详细解答] 此空见文章倒数第二段结尾处，马克·吐温晚年时期，他的妻子和三个孩子都先他而去。