People usuaiiy piant trees in spring every year怎样改为被动语态

问题补充：怎样改为被动语态

最佳回答：

Trees are planted by people in spring every year.

其他回答：

The trees was usuaiiy  pianted in spring every year

仅供参考

Usuaiiy the trees was pianted in spring every year 

People piant trees in spring every year