在图中填写适当的字母或文字。
Y XX XY 男
人的性别由性染色体决定。男性的一对性染色体XY,女性的一对性染色体为XX。精子内的性染色体是X或Y,卵细胞内的性染色体是X。
I often think of the years ____ I worked with the foreigners, ____ has had a great effect on my later life.
A.that; which
B.when; which
C.which; that
D.when; who
杜加(Dugas)氏征是检查()
A.肱骨外科颈骨折
B.肩关节脱位
C.肱骨干骨折
D.肘关节脱位
E.以上都不是