目前用于生产益生素的主要菌种有（）、（）、（）、（）、（）、（）、（）等几大类。
参考答案：乳酸菌；双歧杆菌；粪链球菌；芽孢杆菌；酵母菌；放线菌；光合细菌
阅读理解。
This is a book. It's an English book. It is my English book. That is a
dictionary. Is it Lucy's dictionary? No, it isn't. It's Tom's dictionary. Her
dictionary is in her bag. Look! What are these? They're pens. Are they
Tom's pens? No, they aren't. They are Mike's.
1. What's this? It's _______________.
2. What's that? It's _______________.
3. Is it Tom's dictionary? _______________.
4. Where is her dictionary? ______________.
5. Whose pens are those? ________________.
列车计算制动率的定义？
