According to the rules and regulations, all payments _____ be made in cash in the shopping center.

-----Where is my key? I remember I put it here yesterday.--------You ______  it in the wrong place.

The weather in Inner Mongolia is always dry, but sometimes it _____ rain heavily. 

----Will you take up teaching as a career after graduation?---- Hard to say. I ________ go abroad for higher education instead, but it depends. 

— I think Mr. Zhang may be in his office.— No, he _____ be there. I saw him ____ there just now.