A:for; in
B:after; for
C:as; in
D:after; i
①—Is she seven?
—No, she isn't. She's eight.
②— Is she ten?
—Yes, she is.
③— Is she nine?
— Yes, she is.
④—Is she nine?
—No,she isn't. She's seven.
____
图中①~⑤表示某细胞的部分结构,相关叙述正确的是( )