Mrs. Black doesn’t know if her American friend_____ to Heilongjiang. If he_____ here, she will meet him at the airport.[ ]
You ________ do the work now. You can do it tomorrow.
Where ______ your food?—I only have two hamburgers. They ____ on the table.
What do you think of the math problem ? — It’s very hard and nobody has _______.
Liu Yang is the first Chinese woman astronaut has ever traveled in space.