When Mike was to open the front door,he couldn't find his key.请问这里的be to do是什么用法啊？感觉不符合按照计划、安排即将要发生的动作。
They will pay whoever they find the artist to be，whoever是to be 的宾语吗，那这个不定式是做artist的定语吗?
I hope you will share my delight in watching as simple, even naive, questions lead to remarkable solutions and purely theoretical discoveries find unanticipated applications.请问as是什么成分？watching后是由and连接的两个省略that的宾语从句吗？