Merge two text highlights on ipad


It is often the case that a definition is split by a lot of words in between. This brings the need to select two pieces of highlighted texts and merge them so that when I add them to the mindmap, it generates only one node.

But on an Ipad, I was only able to do this once by accident. I do not know how I can select multiple pieces of highlighted texts (in the reading panel). Does anyone know?