______milk do we need?—Just one cup.[ ]

The book is the most difficult ______ the three. [ ]

I was told to meet Mr. Green at the airport. But I don’t knowhe will arrive.

Is Tom still in New York or already back at home?—I’m not sure _________. I’ll call to make sure.

______ in the near future, vision-phones will come into wider use in our ____ life.