blackadj.黑的；不加牛奶的；很脏的；愤怒的；令人沮丧的；邪恶的；阴沉的；机密的；黑色幽默的n.黑色；黑人；黑色物v.抵制；(使)变黑Blackabyn.布莱卡比

1. Alder trees belong to the birch family.
   赤杨属于桦木科。
2. The microorganisms involved in symbiosis with the alder tree are actinomycetes of the genus Frankia.
   而与赤杨共生的微生物是放线菌。