Sarah is badly ill.She *** see a doctor at once

问题描述:

Sarah is badly ill.She *** see a doctor at once

答案1.Sarah is badly ill.She 【needs to】 see a doctor at once
答案2.Sarah is badly ill.She 【need】 see a doctor at once
答案3.Sarah is badly ill.She 【has to】see a doctor at once
答案4.Sarah is badly ill.She 【should】see a doctor at once