The day before yesterday, I ______ one of my old friends in the street.
| A．meet | B．met | C．will meet | D．have met |
—Your colleague is speaking English with fluency.
—It's no wonder．She ____ in the UK for a year as a visiting professor
| A．worked | B．has worked |
| C．had worked | D．has been working |
The government must be very _____ about setting policies and make no decision until they are quite sure it is the right one.
| A．particular | B．concerned | C．cautious | D．certain |
She says that she'll have to close the shop ________ business improves.
| A．if | B．unless | C．after | D．when |
While ______ himself in the newspaper in a cafe , he got his pocket picked.
| A．having buried | B．buried |
| C．burying | D．to be buried |
— Can you explain ____ you have been late for school several times this term?
— Sorry, but it is the first time that I have been late this week.
| A．why it is that | B．how it is that |
| C．why is it that | D．how is it that |