It was not rare(稀少) in      that people in      fifties were going to school for further study.

A．90s; the

B．the 90s; /

C．90s; their

D．the 90s; their

生理情况下，外周血中平均直径最大的白细胞通常为()

A．嗜酸性粒细胞

B．嗜碱性粒细胞

C．中性杆状核粒细胞

D．中性分叶核粒细胞

E．单核细胞