I think your mother is_____you at the school gate at the moment.

Because of the shortage of coal in England, attempts ________ to use natural gas as a source of power.

It is not until the disease has progressed to AIDS____a person begins to look sick.

call me tomorrow evening, for I ____________to alecture on how to keep a good state of mind when taking an exam.

Is this book____—No, it isn’t. _____is on the desk.