Mr. Black used to be busy. But now he’s retired and , so he has plenty of time to exer cise.
These photos ______ on the Great Wall last week.
If it ______ tomorrow, we’ll go to Bird’s Nest.
—Jim, ________ you answer the last question? -- Sorry, I can’t. It’s too hard.
His father ________ in the factory since he was twenty.
--Be quiet! The children ____________ now. --Oh, sorry.