在工艺流程图中，表示法兰堵盖的符号是。
参考答案：对
The story books___ by the writer in the 1960s. [ ]
A. are written
B. were written
C. wrote
用微信软件传送文字、语音、图片和视频等信息主要体现的计算机网络功能是
A．分布式信息处理
B．数据通信
C．提高系统可靠性
D．资源共享
