干粉灭火器维护与保养:一经打开启用,不论是否使用,都必须进行(),充装时不得变换品种。每个月进行一次外观检查。
A.重新充装
B.使用
C.保管
D.检查
参考答案:A
根据所给句子,选择最佳的应答。每个选项只能用一次。
( )1. What are you supposed to do when you meet Japanese?
( )2. When were you supposed to pick up Jack?
( )3. What did he say?
( )4. Let's drop by our teacher's house.
( )5. Are you used to staying up?
下列有关肌组织的对应关系中,哪项错()。
A.肌细胞—肌纤维
B.肌浆网—粗面内质网
C.肌浆—肌细胞质
D.横小管—T小管