有关哈夫曼编码的方法，以下说法中正确的是（）。

A.哈夫曼编码是一种有损压缩方法

B.编码过程中需要根据符号出现的概率来进行编码

C.编码过程中需要建立"词典"

D.哈夫曼编码的方法不能用于静态图像压缩

The  (1) is a general description of the architecture of a workflow management system used by the WFMC, in which the main components and the associated interfaces are summarized. The workflow enactment service is the heart of a workflow system which consists of several (2).

空白（2）处填（）

A.workflow engines

B.processes

C.workflow threads

D.tasks