A：洋葱鳞片叶
B：根尖细胞
C：青霉菌
D：藓类的叶片
培养细菌或真菌的正确操作步骤是（ ）
①接种 ②配制培养基 ③恒温培养 ④高温灭菌
读句子，选答语。
A. She is my sister.
B. They are in the kitchen.
C. No, they aren't.
D. He's a student.
E. No, she isn't.
-- What are these?
-- __________
