--When _____ the abacus _____? -- In the sixth century by the Chinese people.
| A．is, invented | B．did, invent | C．was, invented | D．does, invent |
I will stay at home and read books if it _______ tomorrow.
| A．is raining | B．rains | C．rain | D．will rain |
She _______ a lot of money on clothes.
| A．takes | B．costs | C．spends | D．buys |
We got mad ______ the team for losing the match.
| A．at | B．in | C．on | D．about |
I got home _____ they were having dinner.
| A．as soon as | B．while |
| C．because | D．after |
---Could we buy a piano, Jack?
---I’m afraid there ______ enough room for one in the house.
| A．aren’t | B．are | C．isn’t | D．is |