Only then do they close in behind the herd. 这时他们才从背后接近野牛群
Only then does the pack finally relent. 这时狼群才会停下脚步
Even then, there are times when more drastic measures are called for. 即便如此 有时也需要更极端的措施
Then there's the sarcastic fringehead. 还有勃氏新热鳚
Then a new species of caterpillar evolves... 然后一种新的毛虫进化而生
They then had to face widespread soil erosion. 导致大量水土流失
Which then decompose into a mixture of water, 之后这些再分解成为 水