所有儿童都种了牛痘以预防天花。

The children were all vaccinated against smallpox.

youdao

种了一次牛痘，起预防作用。

Vaccination has a preventive effect.

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通过种牛痘天花已得到控制。

Smallpox have is bring under control by the use of vaccine.

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孩子们到医院去种牛痘去了。

The kids went to the hospital to be inoculated.

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我种过牛痘了，所以对天花有免疫力。

I'm immune to smallpox as a result of vaccination.

youdao

我种过了牛痘，所以对天花有免疫力。

I'm immune to smallpox as a result of vaccination.

youdao

这就是发现接种牛痘的情况。

That was how vaccination was discovered.

youdao

这就是发现接种牛痘的情况。

That was how vaccination was discovered.

youdao