在双代号网络图中，为了正确地表达图中工作之间的逻辑关系，往往需要应用虚箭线。其作用不包括（）。
A．联系
B．区分
C．辅助
D．断路
参考答案：C
根据句意及首字母提示完成单词，使句子完整通顺。
1. Grace bought a s______in the Gift Shop when he visited Hong Kong.
2. We can see s______in the aquarium.They have big mouths and sharp teeth.
3. I didn't follow you. Can you say your telephone number a ______?
4. Lily is very busy these days. She is studying for the math c______.
5.Why don't you take an u______?It's going to rain.
向忽必烈提议攻打宋朝先攻襄阳的是（）
A、张文谦
B、郭守敬
C、郝经
D、刘整
