It was hard for him to learn English in a family, in which_____ of the parents spoke the language. 

---Would you like tea or coffee, Ayse?---_________ is OK. I really don't mind．

We could not understand them because        of us know their language.

There are lots of flowers on ______ sides of the street.

_______ is believed, all the scientists subscribe to the view ______ the increase in the earth’s temperature is due to the burning of fossil fuels to produce energy.