The science of computer, _______rapid progress has been made in recent years, is the most important of all science.
Did ____ on time make her teacher angry?
---Next Monday is my birthday. ---Is that so? ____ ---Thank you.
What surprised me was not what he said but ____ he said it.
You think you’re poor, but look at the people in really poor countries─it’s all ____.
____ my sister three times today but her line was always busy.