Tony and I are good friends. We tried to walk across the United States of America. We're not exactly sure 　小题1:　 we were doing it. Part of it was to test ourselves; to see if we could face the challenges. When I was 　小题2:　 teenager I often daydreamed that I was going to walk across the United States 　小题3:　I graduated from high school. 　 小题4:　，I didn't do that. Before I knew it I was in my thirties, married, 　 小题5:　 (have) a job, yet still had this idea in my mind with each　小题6:　(pass) year. I figured I was too old and my opportunity had passed. Then, a few years ago，I met Tony,　 小题7:　 was in his thirties and quit his job as a civil engineer in New York City to walk across the United States. He wasn't doing it for a cause　小题8:　 as part of an organization. He was doing it　小题9:　（simple) because he loved to walk and discover. The idea was back and I no longer had an excuse. We planned on averaging 20 miles a day and taking some days off to rest, so we expected the walk to. take about 6 months realizing it could take　小题10:　（long). We were in no hurry: The total distance would have been about 3,100 miles.

参与SIgA分泌的细胞有（）.

A.浆细胞

B.微皱褶细胞

C.吸收细胞

D.树突状细胞

E.杯状细胞