英语语法分析

Hevea can yield four or five times that figure.

橡胶树产量可以达到这一数字的4、5倍。

If they could be turned into usable crops, they could outstrip even Hevea.

如果能将它们变成有用的作物，它们甚至会胜过橡胶树。

The two-part rubber tree (Hevea brasiliensis) is a superior clone grafted on a seedling family.

在橡胶树优良有性系实生苗上嫁接优良无性系，即形成两合树。