—Ready to give up guessing, Sandy? —No, no. Hold on! I think I _______ at the answer now.
While working in the countryside , the students ________ a great deal of knowledge on plant life.
. By the time she ________ tomorrow, the work ________.
Some people waste a lot of food ________ others haven’t enough to eat.
When and where to build the new factory _____ yet.
I have many friends, ________ some are businessmen.