淋巴干细胞发育成T淋巴细胞的刺激因子是（）

A.集落刺激因子

B.特异性抗原

C.调理素

D.胸腺激素

E.促淋巴细胞生成素

Some of the low-end Made-in-China mechanical-electronic products are not selling well in export market as compared with what are termed as high-end ones.

A．on export market

B．in exporting market

C．in exported market

D．in the export market