He took the medicine at one swallow.

他一口把药吞了下去。

youdao

He downed his whisky in one swallow.

他一口喝下威士忌。

youdao

One swallow does not make a summer.

一燕不成夏。

《新英汉大辞典》

"One swallow doesn't make a summer, " says Meileen Choo, chief executive of film producer and distributor Cathay Organization.

CNN: GAINING CULTURAL CAPITAL

One swallow does not a summer make, of course.

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"For the high street, one swallow does not make a summer, but these results might hint at the green shoots of recovery, or at least some stabilisation in the current environment, " Ms Wehrle added.

BBC: Shopper