___ himself in carrying out an experiment, he can’t spare time to look after his children.
| A．Occupied | B．Having occupied | C．Occupying | D．Having been occupied |
The girl looked at me with a _______expression. Maybe the problem was quite _________.
| A．puzzled; puzzling | B．puzzling; puzzled | C．puzzled; puzzled | D．puzzling; puzzling |
A great number of students ______ said they were forced to practise the piano.
| A．to question | B．to be questioned | C．questioned | D．questioning |
Was it in the village _______ he was born ________ the talented journalist met the retired professor?
| A．that, where | B．where, which | C．which, where | D．where, that |
It is worthwhile considering what makes “convenience” foods so popular, and____ better ones of your own.
| A．introduces | B．to introduce | C．introducing | D．introduced |
__________ to sun, rain and wind for a long time, the stone split.
| A．Being exposed | B．Having exposed | C．Exposed | D．To expose |