英语翻译天气预报很重要,依据它我们才能决定什么时候起航翻译：Weatherforecast is so importan

Weather forecast is so important that based on it,we can decide when to set sail.
或者
Weather forecast is important for that/in that we have to depend on it in order to decide when to set sail.
或者
Weather forecast,on which we depend to decide when to set sail,is important.
您出错的原因是因为So...that 从句后面必须跟一句完整的句子,.您把that后面的句子提出来念得通,成一句句子才可以.而depend on which can we...只是一个从句的形式.