Match the meanings

{"params":{"media":{"disableImageZooming":false},"content":{"task":"<p>Six words are marked in blue in the column. Read the sentences and choose the word that has the same meaning in the context.<\/p>\n","blanksList":[{"correctAnswerText":"stand-in"},{"correctAnswerText":"shift"},{"correctAnswerText":"essential"},{"correctAnswerText":"aroused"},{"correctAnswerText":"unending"},{"correctAnswerText":"filled"}],"blanksText":"<p>1. I first heard of this novel when I was asked to be the last-minute ________ (<span style=\"color:#3498db;\"><strong>substitute<\/strong><\/span>) host of a book club where it would be discussed.<\/p>\n\n<p>2. For example, there\u2019s a single narrator in the audio version, which I found made the frequent ________ (<span style=\"color:#3498db;\"><strong>switch<\/strong><\/span>) between stories rather confusing.<\/p>\n\n<p>3. I did later read about Diogenes and learned that he had been a real person, but that his manuscript, which is ________ (<span style=\"color:#3498db;\"><strong>core<\/strong><\/span>) to the novel, is fictional.<\/p>\n\n<p>4.&nbsp; Viewing the characters through this lens has indeed ________ (<span style=\"color:#3498db;\"><strong>piqued<\/strong><\/span>) my interest.<\/p>\n\n<p>5. It\u2019s the ________ (<span style=\"color:#3498db;\"><strong>everlasting<\/strong><\/span>) human struggle to survive, to find one\u2019s place in history, and to overcome fear and loneliness.<\/p>\n\n<p>6. It\u2019s well written, intelligent, ________ (<span style=\"color:#3498db;\"><strong>brimming<\/strong><\/span>) with ideas, moving, and deeply insightful.<\/p>\n"},"overallFeedback":[{"from":0,"to":100}],"behaviour":{"mode":"selection","selectAlternatives":"all","selectAlternativeRestriction":0,"spellingErrorBehaviour":"mistake","caseSensitive":false,"autoCheck":false,"enableSolutionsButton":true,"showSolutionsRequiresInput":false,"enableRetry":true,"enableCheckButton":true,"confirmCheckDialog":false,"confirmRetryDialog":false},"showSolutions":"L\u00f6sung anzeigen","tryAgain":"Wiederholen","checkAnswer":"\u00dcberpr\u00fcfen","submitAnswer":"\u00dcbermitteln","notFilledOut":"Bitte f\u00fclle alle L\u00fccken aus, um die L\u00f6sung ansehen zu k\u00f6nnen","tipLabel":"Tipp","spellingMistakeWarning":"\u00dcberpr\u00fcfen Sie die Rechtschreibung","scoreBarLabel":"Du hast :num von :total Punkten erreicht","confirmCheck":{"header":"Beenden?","body":"Ganz sicher beenden?","cancelLabel":"Abbrechen","confirmLabel":"Beenden"},"confirmRetry":{"header":"Wiederholen?","body":"Ganz sicher wiederholen?","cancelLabel":"Abbrechen","confirmLabel":"Best\u00e4tigen"}},"metadata":{"license":"U"}},