频度副词的概念：

频度副词表示动作发生的次数，常见的有ever, never, rarely, seldom, once, often, occasionally, constantly, frequently, usually, continually, always等。

频度副词的特点：

频度副词表示动作发生的次数，常见有的ever, never, rarely, seldom, once, often, occasionally, constantly, frequently, usually, continually, always等。

频度副词在句中的位置：

频度副词通常位于实义动词之前，动词be、助动词、情态动词之后：
如：He often comes to see us. 他常来看我们。
        He is seldom late for school. 他上学很少迟到。
有时为了强调，频度副词也可位于动词be、助动词等之前：
如：She always was late. 她老是迟到。
有的频度副词可位于句末（尤其受very, only修饰时）：
如：I get paid on Fridays usually. 我通常在星期五领工资。
        We go out very seldom. 我们绝少外出。
        Do you go to the cinema very often? 你常去看电影吗?
有的频度副词（如sometimes, often, usually, frequently, occasionally等）可位于句首（此时多半是因为强调或对比）：
如：Sometimes he went there by bus. 有时他坐公共汽车去那儿。
        Very often the phone rings when I'm in the bath. 电话经常在我洗澡时响。
注：含有否定意义的副词置于句首时，其后要用倒装语序：
如：Never have I been there. 我从未去过那儿。
        Seldom does he see a film. 他很少看电影。
另外，频度副词always和never通常不位于句首，除非是祈使句：
如：Always remember this. 时刻记住这一点。
        Never go out at night. 晚上千万不要出去。

频度副词在否定句中的位置：

在否定句中，有的频度副词可位于否定词not之后或之前（如usually,often），有的频度副词则必须位于否定词之后（如always, constantly, continually, continuously，均含有“连续不断”之意），而有的频度副词却必须要位于否定词not之前（如sometimes, frequently）：
如：He doesn't usually come here./He usually doesn't come here. 他通常不来这儿。
        She doesn't always comelate. 她并非总是迟到。(不能说alwaysdoesn’t)
        He is sometimes not responsible for what he does. 他有时对他所做的事不负责任。