Sorry to say it will be years _______ we really have classes here with only 25 students.
| A．since | B．that | C．when | D．before |
—Did any signs come up before the earthquake?
—Yes. Unusual things all those days. For example, a number of animals got out their homes.
| A．happening | B．were happening | C．has happened | D．had happened |
The agent was about to sign his name to the document ________，to our surprise，a stranger broke in to prevent him.
| A．while | B．when | C．as | D．until |
— Do you know __________ they got to know each other?
— It was last year ________ they both taught English in China.
| A．when was it that; when | B．when it was that; that |
| C．when it was that; when | D．when was it that; that |
— It’s no easy task to catch a ticket on a website that receives 1 billion clicks daily.
—I can’t agree with you more. There ________ be errors for every single step.
| A．should | B．must | C．will | D．can |
—I wonder what makes you a successful manager.
—I ________ as a waiter for five years，which contributes a lot to my today’s work.
| A．serve | B．have served | C．had served | D．served |