I think you will be able to catch the train,--------

不是!应该是：won't you?
陈述部分--是think/believe/suppose (表示“认为；猜测”类动词)引导的复合句(即宾语从句)时,疑问部分：
1 当主句的主语是第一人称时,则和从句保持一致.如 I believe Miss Wang is right, isn’t she? / We don’t think you can answer so difficult a question, can you?
2 当主句的主语不是第一人称时,则和主句保持一致.如 He thinks he can mend this bike, doesn’ t he?
本句应与从句保持一致.
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