单项选择题
A．Trim the apple trees in her yard. B．Pick up the apples that felt in her yard. C．Take the garbage to the curb for her. D．Remove the branches from her yard.
A．Bad weather. B．Human error. C．Breakdown of the engines. D．Failure of the communications system.
A．The crop’s blooming period is delayed. B．The roots of crops are cut off. C．The topsoil is seriously damaged. D．The growth of weeds is accelerated.