“Look at these tracks. It _______ be a wolf.” “Don’t be so sure. I think it _______ be a fox.”
| A．must; could | B．may; might |
| C．need; must | D．could; need |
The astronaut did many experiments in the spaceship,__________________much help for knowing space.
| A．which we think it is | B．which we think are of |
| C．of which we think is | D．I think which is of |
Once ____________ , a plan should be carried out.
| A．make | B．making | C．made | D．to make |
—"How do you like the book?"
— "It's quite different from I read last month."
| A．that | B．which | C．the one | D．the one what |
He failed in the examination, ________ made his father very angry
| A．which | B．it | C．that | D．what |
I had _________good lunch at ________ restaurant __________ we met for the first time.
| A．a, a, which | B．the, the, where | C．a, the, where | D．\, the, that |