I’m writing this letter ________ mymother, who wants to thank you for your nice gift.

ts are required to go out in couples, especiallyin the evenings, with friends ______ they get into trouble.

Any news about Bill Clinton? —-He left power three years ago and has a little now and a little then been ______

Which has a different sound from the other three

________ energy is generated from natural resources—such as sunlight, wind, rain, tides and so on.