单项选择题In discussing Landes's work, the author's tone is ______.
单项选择题This school (para. 5) refers to people who ______.
单项选择题According to Landes, the main reason that some countries are so poor is that ______.
单项选择题The cultural elements identified by Landes ______ those identified by other historians.
单项选择题Landes believes that ______.