The disappearance of dinosaurs is not necessarily caused by astronomical incidents. But _________explanations are hard to find.
| A． |
alternative |
B． |
aggressive |
C． |
ambiguous |
D． |
apparent |
I____ my homework at nine o'clock last Sunday morning.
| A．am doing | B．was doing |
| C．do | D．did |
Look at the pride on Tom's face. He ____ to have been praised by the manager just now.
| A．seemed | B．seems |
| C．had seemed | D．is seeming |
Professor John will give us a lecture on how to learn English, but when and where ____ yet.
| A．hasn’t been decided |
| B．haven’t been decided |
| C．isn’t decided |
| D．aren’t decided |
He asked me how much ____ on the mountain bike.
| A．did I pay | B．I paid |
| C．had I paid | D．I had paid |
I haven’t finished my report, but I promise I ____ it by the end of the week.
| A．will finish |
| B．have finished |
| C．will be finishing |
| D．will have finished |