Copying from SMS to clipboard, how to open the clipboard and then copy it to Youdao dictionary?

The one with the arrow, the second from the left at the bottom! In the input mode of editing short messages. You can press this key and then use the arrow keys to choose, just like clicking the left key on the computer to choose. When you choose to release this button, these options will pop up, copy and cut (for example, if you copy, press and hold this button where you want to paste, and an option will pop up after release).