肾移植术前，组织配型检查项目不含

A．ABO血型

B．HLA抗原

C．3P试验

D．混合淋巴细胞培养

E．淋巴细胞毒性试验

It    be difficult to get a train ticket during traditional Chinese Spring Festival this year because there are many ticket windows.

A．mustn't

B．ought to

C．needn't

D．can't