实验室灭火的方法要针对起因选用合适的方法。一般小火可用湿布、石棉布或沙子覆盖燃烧物即可灭火。
参考答案:对
— Did Lucy go to work today?
— Yes, she did, ______ she was not feeling very well. [ ]
A. though
B. until
C. or
D. because
数据流图中各构成元素的名称不一定必须具有明确的含义以代表对应元素的内容或功能。