be adj to do还是to be done例如：This machine is very easy_.Anybody can learn to use it in a very short time.为什么填to use而不是to be used
问题描述：
be adj to do还是to be done
例如：
This machine is very easy_.Anybody can learn to use it in a very short time.
为什么填to use而不是to be used
答
This machine is very easy（for us）to use
省略了 for us，我们和使用之间是主动的关系
答
to use
因为此句型中句子主语是不定式的逻辑宾语, 而非逻辑主语
再如：
He is easy to get along with
The question is easy to answer
The apple is good to eat.
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