她说，“去年，当西非某个地区的薄弱卫生计划造成脊髓灰质炎在西非流行时，我们看到了这种效应。

We saw that last year when the polio epidemic reemerged in West Africa due to weak health care programs in one area of that region.

youdao

她说，“去年，当西非某个地区的薄弱卫生计划造成脊髓灰质炎在西非流行时，我们看到了这种效应。

We saw that last year when the polio epidemic reemerged in West Africa due to weak health care programs in one area of that region.

youdao