The world's first flying car has been ________ for sale at ￡800,000 by Courtesy Aircraft of the US.

A．taken up

B．put up

C．pulled up

D．made up

打破自身耐受的原因之一是

A．与自身抗原有相似结构成分的微生物进入体内

B．Th细胞功能障碍

C．Ts细胞增多

D．免疫系统不间断地与低剂量自身抗原接触

E．内源性可溶性抗原的产生