In 'walk slowly', the adverb 'slowly' modifies the verb 'walk'.

在walk slowly中，副词slowly修饰动词walk。

《牛津词典》

Try to do everything a little more slowly. Besides working at a more reasonable pace, try to walk, talk, drive and eat more slowly.

做什么事都试着慢一些，除了合理的工作节奏，让你的走路、说话、开车和吃饭都慢一些。

youdao

Think of it in three parts: a five-minute warm-up of walking slowly, followed by a fast walk, then a five-minute cool-down of walking slowly.

考虑三步走：一个五分钟慢走的热身，紧接着是快走，然后是一个五分钟慢走的冷却。

youdao

They are known for their ability to walk slowly and safely on the paths.

VOA: special.2009.10.07

Adults and children can be seen testing it as they walk slowly in and out of the thick haze.

BBC: Look on the bright side at London��s light show

Soon I flub a shot, and my son encourages me to take it easy: "Just walk slowly and clear your head, " he says.

WSJ: How Mom Plays the Game | Golf Journal

Surprisingly, after three months of therapy 90% of those with some sensation and movement recovered the ability to walk slowly, no matter which type of training they had gotten.

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