I don’t think that inference is a skill and I don’t think that inference is something that can be developed in isolation. Children can only “read between the lines” when they understand the vocabulary, the context, and how people behave. When they struggle with inference questions, it’s not about a general lack of ability to infer but rather the knowledge gaps underneath it. After a quick explanation of what inference is and how to answer those questions, the most effective thing you can do is read quality books together, talk about words and feelings, and build their knowledge of the world. That’s what actually grows inference.