视频对话：
...About what?
……为了什么？
The situation is very fluid.
情况很多变。
If he refuses to deal with Cuba, then Cuba is going to deal with him.
如果他古巴合作，那么古巴会找他麻烦。
本期学习词汇：
fluid
n.液体，流体
adj.流体的，流动的，流体的，液体的；易变的，不固定的；（动作、设计、音乐等）流畅优美的
例句：
1. Make sure that you drink plenty of fluids.
务必保证足够的水分摄入。
2. The situation is extremely fluid and it can be changing from day to day.
情况极不稳定，每天都有可能变化。
3. U.S. officials admitted that they were still trying to get a handle on the fluid situation.
美国官员承认，他们仍在努力了解把握瞬息万变的形势。
4. The forehand stroke should be fluid and well balanced.
正手击球应该保证动作流畅和平稳。
5. He made himself understood as much by the gestures of his hands as by his fluid English.
他用流畅的英语及手势来说明自己的意思。