Only when _______ 30 years old ______ to learn English.
| A．was he; did he begin | B．he was; he began | C．he was; did he begin | D．was he; he began |
When first ________ to the market, the computer software ． was not a success due to its complexity in operation.
| A．introducing | B．being introduced | C．introduced | D．to be introduced |
After a 5-year absence, we returned to our mother school, and not until then it was such a beautiful school.
| A．we realized | B．had we realized | C．we had realized | D．did we realize |
—Mary said Leo worked really hard.
— _______.
| A．So does he and so does she | B．So does he and so she does |
| C．So he does and so she does | D．So he does and so does she |
—We could invite John and Barbara to the Friday night party.
—Yes, ______ ? I’ll give them a call right now.
| A．why not | B．what for | C．why | D．what |
I have been living in the United States for twenty years, but seldom_______ so lonely as now.
| A．have I felt | B．I had felt | C．I have felt | D．had I felt |
Not until ___ on TV ___ that the Chinese was rescued by the European Union Task Force.
| A．did I turn; did I know | B．did I turn; I knew |
| C．I turned; did I know | D．I turned; I had know |
_______ let fake products become uncontrolled in the market.
| A．In certain circumstances we can |
| B．In no circumstance can we |
| C．Under any circumstances we can |
| D．Under no circumstances can we |
Not until ___ on TV ___ that the Chinese was rescued by the European Union Task Force.
| A．did I turn; did I know | B．did I turn; I knew |
| C．I turned; did I know | D．I turned; I had know |
_____________ late, but also he forgot his books.
| A．Not only did he turn up | B．Not only he turned up |
| C．Not only did he turn out | D．Not only he turned out |