i've come across a problem on sheet 4 where i can't get high pitched notes to play for more than a quarter length (you will see the part it has alot of repeating eighth notes) could someone tell me how to fix this

<p><iframe width="100%" height="180" src="https://embed.notessimo.net/?oembed=1&url=https%3A%2F%2Fnotessimo.net%2Fs%2F74991" frameborder="0" scrolling="no" seamless="seamless" sandbox="allow-same-origin allow-scripts allow-forms allow-popups allow-popups-to-escape-sandbox allow-presentation"></iframe></p>\n<p>i’ve come across a problem on sheet 4 where i can’t get high pitched notes to play for more than a quarter length (you will see the part it has alot of repeating eighth notes) could someone tell me how to fix this</p>