In those days our primary ______ was to provide people who were trapped in the snowstorm with food and healthcare.
| A．anxiety | B．concern | C．incident | D．doubt |
“Would you mind my sitting here with you?” “No, ______ you aren’t too noisy.”
| A．when | B．if |
| C．unless | D．as soon as |
“Shall Mary come and play computer games?” “No, _______ she has finished her homework.”
| A．when | B．since |
| C．unless | D．as soon as |
_______ the sun rising slowly in the east, the scene is a perfect dream.
| A．Seeing | B．To be seeing |
| C．When you see | D．Having seen |
______ for something, a receipt is given to you.
| A．Paying | B．Having paid |
| C．When you have paid | D．To be paying |
_______ a pair of compasses, it is easy to describe a circle.
| A．Having | B．To have had |
| C．If you have | D．if having |