还是不要死记硬背的好，永远记住一个句子中只能有一个谓语就够用了。无论怎么变都不会出错。The men working on the site were in some danger.其中man是主语（非谓语），working on the site是定语，were是真正的谓语。
换成The men who were working on the site were in some danger.时， who were working on the site仍是定语（从句），were仍是谓语，句子没有问题。 The men who are good for people are standing there，其中who ...
