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.
单项选择题 标志和文字同出一源，由原始的（ ）发展而来。标志是以精炼的形象表达一定的含义。
单项选择题 按照次序规则，下列基团为较优基团的是：
