根据句意和首字母提示补全单词

       Do you k   1   Nie Haisheng and Fei Junlong? They are b  2   astronauts(宇航员). They went(去) to

the space(太空) by(乘) the Shenzhou Ⅵ spacecraft(宇宙飞船). They are cool. They are in gray c  3  

then. They f  4   the earth(地球) is small. Mr.Nie and Mr.Fei are good friends. They are o  5   pride

(骄傲).

试述照射量和吸收剂量的概念。