Sandy is so careful that she ________makes mistakes in her homework．

A．usually           B．seldom          C．often              D．always

1、B  考查频度副词。句意“Sandy如此细心以至于她的作业中几乎没有错误。”usually“通常地”；seldom“不常；很少”；often“经常”；always“总是”。结合句意可知正确答案为B。