I need one more stamp before my collection _______.
| A．has completed | B．completes | C．has been completed | D．is completed |
—Lily is going to make a presentation in class this afternoon.
—Oh, really? I ________ it was Michael's turn.
| A．think | B．have thought |
| C．thought | D．am thinking |
The house is dirty because it ________ since they moved out.
| A．doesn't clean | B．isn't cleaned |
| C．hasn't cleaned | D．hasn't been cleaned |
Now we have arrived at the lake. But the view I photographed that day ________ any more.
| A．doesn't exist | B．isn't existing |
| C．hasn't existed | D．hadn't existed |
Up to now, our society ________ with limited living space and a shortage of natural resources.
| A．has been challenged | B．is being challenged |
| C．is challenging | D．has challenged |
—Will you see me off at the airport at ten tomorrow morning?
—Sorry, I ________ a lecture then.
| A．will be giving | B．will give |
| C．give | D．have given |