事故预警管理系统同企业内部其他职能系统的关系由（）方式所规定。
A.“组织设计”
B.“组织运行”
C.“日常监控”
D.“组织准备”
参考答案：B
Tom wants to be a singer and he_____. singing lessons to do it. [ ]
A. took
B. has taken
C. is taking
D. was taking.
被子植物的主要特征是什么？
