单项选择题 盐酸吸收塔的液位要求控制在0.2-1.5m之间，因为盐酸吸收塔渗漏，正常生产时吸收塔液位控制在（）

单项选择题 Delivery (or delivery) process. This is the end operation of the distribution center, and also an important part of the whole distribution process. It includes ( ) two economic activities. A. Packaging and loading B. delivery and collection C. loading and delivery D. inventory and delivery

判断题 Each party in serial communication can set its own baud rate.