The town was named ________ the hero who devoted his life to the development of the area.
A. for
B. after
C. to
D. of
Scientists warn the government to take the environment into ________ when developing the local economy.
A. considering
B. thought
C. account
D. mind
George had to stay at home during holidays _________ he could help his father look after the farm.
A. so as
B. now that
C. because
D. so that
Look at the terrible mess! You _________ cleaned the house before I came back.
A. should have
B. must have
C. will have
D. had