Spending______ Christmas in a foreign country with local people was really _____ unforgettable experience for me.

A．\;an

B．\;\

C．the; an

D．the; \

预防幼儿急疹的方法是（）。

A.接种疫苗

B.肌注胎盘球蛋白

C.肌注丙种球蛋白

D.肌注利巴韦林

E.以上都不是