Where is Mr.Lu?询问现在人在哪里,表明回答中也是【现在人在哪里】.
I'm not sure.【Isn't】he【writing】(write)in his office?
现在进行时,表明说话的此时此刻“难道他此时不是正在他办公室书写吗?”
祝你开心如意!