Could you drive me to the supermarket after supper if _________________?

ere is less coal and oil, scientists are exploring new ways of making use of _____ energy, such as sunlight, wind, and water for power and fuel.

________ caused the accident is still a complete mystery.

o you think of his talk on InformationTechnology —Oh, excellent. It’s worth ________．

Wouldyou like to have some milk 一__________