产生IL-2的细胞是
A．MΦB．TC．BD．NKE．中性粒细胞
参考答案：B
It was because I was ill ________ I didn’t go to school.
A．why
B．that
C．which
D．when
叩击人膝盖下的韧带时，会发生______反射．这种反射属于______反射．
