副词本身要用 副词来修饰。例如：

1. He is a very careful driver.

2. He drives his car carefully.

3. He drives his car very carefully.

在某些情况下，副词也可以用其他类型的副词来修饰，但这种情况较少见。例如：

1. He speaks English very well.

此外，还可以用一些表示倍数的词或度量名词作修饰语，但这些词通常置于比较级形容词或副词的前面。例如：

1. He runs twice as fast as his brother.

建议在实际使用中，根据具体的语境和需要选择合适的副词进行修饰。