The employees?more enthusiastic about their work since their pay

The employees?more enthusiastic about their work since their pay rose．
A、Are
B、have been
C、Were
D、will be
【正确答案】：B
【题目解析】：【考情点拨】考查时态。 【应试指导】句意：自从涨了工资，员工们工作起来更有热情了。since表示“自从……”，出现在句中时．主句要用完成时，故选B。