可以作系动词的动词

常见的除上以外还有, keep, remain, stay, prove, stand
其实有更多,只是不常见,请参见这里:

http://www.hongen.com/eng/pub/yufac/0501.htm

look是一个，
seem也是一个，如：He seems very happy.
feel又是一个，如：I feel angry.
sound还是一个，如：It sounds good.
暂时只能想到这么多啊。

become