A.assumption
B.consumption
C.presumption
D.resumption
A.a special way of thinking
B.enthusiastic workers
C.the attractive premium system
D.elementary school
A.They had received privileged home training.
B.They contributed to disciplined school management.
C.They are the result of technological development.
D.They benefited a lot from their mathematical knowledge.
A.was an American invention
B.appeared before the patent system
C.is as important as the patent system
D.is supported by the federal government