Given two large articles, please search and return for all the sub-sentences which existing in both articles. The sub-sentence is required at least more than three words.\n\n**Example 1:**\n```\nInput: a = "today is sunny and okay I feel yes so happy", b = "tomorrow is sunny and that makes today is sunny and okay me feel yes so happy too"\nOutput: ["is sunny and", "feel yes so happy", "today is sunny and okay"]\n```

Given two large articles, please search and return for all the sub-sentences which existing in both articles. The sub-sentence is required at least more than th