Countries are looking for new clean fuels, such as solar energy, ________their homes in winter.    [ ]

A. to heat      

B. heating        

C. heated      

D. having heated

---He was nearly killed by a car once.

---Oh, when was _____ exactly?

---It was in 2007 _____ he was riding a bike on the drive-way.

A．this; that

B．that; when

C．that; that

D．this; when