---Look! The light is still on. Is Mr Wu working in his office？---No, it _____ be Mr Wu. He has gone to Nanjing for a meeting. 

 Thanks to his pension, Li Zhentian, _____ give each of his grandchildren RMB 5 as a Chinese New year gift for the first time.

—Excuse me. Is this the right way to the Summer Palace? —Sorry, I am not sure, but it ____ be.

We were looking for you all this morning. You    office without a word.

I ________ work out the problem at first, but after my teacher showed me an example, I ________ get the answer easily.