然而，当证据开始积累的越来越多的时候，动物园的科学家感觉到有必要去调查。

However, as the evidence began to accumulate, experts from the Zoo felt obliged to investigate.

youdao

然而，当证据开始积累的越来越多的时候，动物园的科学家感觉到有必要去调查。

However, as the evidence began to accumulate, experts from the Zoo felt obliged to investigate.

youdao