器官移植的困难是机体对移植器官的排斥，这是因为植入器官的组织细胞相当于（）
A：病原体
B：抗原
C：抗体
D：受损伤的组织
22的值是____ 7绝对值是 ____ ；____的立方根是﹣2；平方根和立方根相等的数是____
排序。
A. There are five books on the table.
B. It's small, but it's clean.
C. There is a doll on the bed.
D. Look! This is my room.
E. I like my room.
F. There is a table and a bed in my room.
____
我国最长的内流河和最大的沙漠在（ ）
