Slowly and stealthily, someone was creeping up the stairs.

蹑手蹑脚地，有人正爬上楼梯。

《柯林斯英汉双解大词典》

They went tiptoeing stealthily down, the one behind the other.

他们一前一后蹑手蹑脚地悄悄走了下去。

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He started swiftly and stealthily, and just as he was crossing the threshold he heard voices behind him.

他飞快地、鬼鬼祟祟地迈步往前，正当他要跨进门槛，就听见背后有说话声。

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Suddenly, stealthily, last month Chancellor Gerhard Schrder proposed abolishing the corporate capital gains tax.

FORBES: Fact and Comment

If only insurers could stealthily gather a few titbits about their potential policyholders' consumption habits.

ECONOMIST: Loyalty cards and insurance

Think about that as your hybrid runs stealthily on battery power, brought to motion by the conductivity of copper.

FORBES: The Environmental Protection Agency Comes-a-Copper