—Tomorrow ____ my birthday. I’d like you and Jane to come.

—I’m not sure if she ____ free.

A．will be; is

B．is going to; is

C．is; is

D．is; will be

砌筑砂浆试块强度验收时，其强度合格标准，同一验收批的砂浆强度平均值应大于或等于设计强度等级的（）倍。