中国林科院的韩一凡研究员告诉我们，北京从20年前开始种植毛白杨，北京目前70%的树木都是这一树种。

Han Yifan, a Chinese Academy of Forestry researcher, told us that Beijing began planting cottonwood poplar trees about 20 years ago and that about 70% of the city's trees are now this species.

youdao

中国林科院的韩一凡研究员告诉我们，北京从20年前开始种植毛白杨，北京目前70%的树木都是这一树种。

Han Yifan, a Chinese Academy of Forestry researcher, told us that Beijing began planting cottonwood poplar trees about 20 years ago and that about 70% of the city's trees are now this species.

youdao