用participate的适当形式填空

1. All the          in the debate will have an opportunity to speak.93. Union leaders called

for the active            of all members on the day of protest.

2. I'll             in your suffering and joy.

髓母细胞瘤的组织学特点是（）

A.瘤细胞呈栅栏状排列

B.肿瘤出血、坏死明显

C.瘤细胞形成纤维心菊形团

D.瘤细胞围绕血管形成菊形团

E.瘤细胞呈上皮样