The video will stay in view as you scroll down following the text. If you want to 'pause' or 'repeat' a sentence, it's very simple. Use your 'spacebar' for 'pause/play' and you can click on any text and the audio will play that line (and continue playing, unless you hit 'spacebar' to pause it). And just one click is enough. No need to double click on the line you want to listen to.
If the video doesn't play, or the control features don't work, please upgrade your browser or try Google Chrome.