判断题 虽然二因素方差分析中涉及三个假设检验，但是一定要使用同一个显著性水平。()

未知题型 Modem agriculture is criticized as unsustainable becauseA．it promotes the erosion of topsoil.B．it cannot provide a long-term planning.C．300 years is not long enough for the development.D．the lost topsoil is irreplaceable.

未知题型 The U.S. Department of Agriculture played an important role in agricultural developments byA．adopting hybrid seeds and genetic engineering of plants.B．advocating the wide use of fertilizers and pesticides.C．improving the environmental conservation of lands.D．providing farmers with extension service of education.