15辆卡车用8次运了600吨苹果，一辆卡车一次运多少吨苹果？
600÷15÷8，
=40÷8，
=5（吨）；
答：一辆卡车一次运5吨苹果．
According to the psychoanalyst Sigmund Freud, wisdom comes from the _____ of maturity.
A．fulfillment
B．achievement
C．establishment
D．accomplishment
