Lucy will have learned English for 8 years by the time she ____ form the university next year.

A．will graduate

B．will have graduate

C．graduates

D．is to graduate

液压系统不允许在低温时由于油太粘稠而影响控制的准确性，要求在低温工作环境下也能保证足够的可靠性和快速性。所以，液压油的（）应更低一些。