参与淋巴细胞归巢的粘附分子是（）
A.CD44
B.VLA-4
C.LFA-1
D.CLA
E.L-选择素
参考答案：A, B, C, D, E
The school rule states that no child shall be, unless _by an adult, allowed out of the school during the day.
A．to be accompanied
B．accompanying
C．accompanied
D．being accompanied
WHO建议，按照60岁以上老年人口系数达到多少百位比为老年型社会（）
A.5％
B.10％
C.15％
D.20％
E.25％
