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
----What’s that noise?
---- There’s a truck stopping outside．It’s someone something.
A．deliver B．to deliver C．delivering D．delivered
After the trainer was sure that the whale could look after itself, he _______ it into the sea.
A. transported B. delivered C. released D. handled
