谁能告诉我下appear to be与 appear to do的区别吗?谢谢

题目

谁能告诉我下appear to be与 appear to do的区别吗?谢谢
If they speak for themselves,they may appear to be flattering their boss for favors.
为什么这里不是用 appear to do 呢?
顺便帮我分析下动词时态 这是真实条件句 还是虚拟条件句？据我观察 这应该是真实条件句 动作发生在现在 时态就是一般现在时 主句和从句时态一致的？搞不懂啊 ···

答案

appear to be：好像是,仿佛；强调状态
appear to do：好像做了某事；强调做了.事
如果后面不是"flattering"而是"flat"就用"appear to",因为"flat"就是do的形式了.