二、請說明「飛航時間」、「飛航執勤期間」與「執勤期間」之定義，並依時間序列繪圖比較三者之差異。（25 分）

一、英譯中：請將下面這段英文譯成正確、流暢的中文（10 分） Before the pandemic, there were many reasons to be anxious about taking an elevator — from being crammed in a small space with strangers, to getting stuck between floors. Now, as COVID-19 cases exceed 20 million worldwide, many people are concerned about catching the virus, whether from someone else in the elevator or via the buttons.