The ______ feature is considered central to human language, which means two levels of "structure"or "patterning".

单项选择题The tone of this text is ______.

单项选择题According to the text the newsagent last wrote out Topham’on the top right-handed comer of the author's paper because ______.

单项选择题The research reviewed in the passage suggest that ______.

单项选择题Helsing speculates that husbands suffer from the death of a spouse because they are ______.

单项选择题One of the results of grief mentioned in the passage is ______.