「inevitable」是不可避免、必然會發生的，例如：

Some of the students seem to think that this defeat is inevitable.（有些學生似乎認為，這種失敗是不可避免的。）

There will be inevitable consequences, which mold the future.（會產生不可避免的後果，將塑造未來。）

You’ll have to compromise to the inevitable.（你將不得不向無法避免的事妥協。）

optional

「optional」是隨意、非必要的，例如：

For the graduate party, the formal dress is optional.（參加畢業聚會，不強制穿著正式禮服。）

Extracurricular include cooking lessons at a top restaurant, It is optional for senior students.（課外科目包括頂級餐廳的烹飪課，可供高年級學生選擇。）

There are several optional day tours, for which there will be a small charge.（有幾個一日遊行程任選，收費也不多。）

Bob Marley

巴布．馬利有一則小故事，在由威爾史密斯（Will Smith）主演的電影《我是傳奇》（I Am Legend）中描述，藉以表示拯救全人類「捨我其誰」的堅決意念：

One day, Bob Marley was scheduled to perform at a peace rally. Gunmen came to his house and shot him down. Two days later, he walked out on that stage and sang. Somebody asked him why. He said,”The people who are trying to make this world worse are not taking a day off. How can I?”

一日， 巴布．馬利在家中正在為和平大會演出籌畫安排，被歹徒持槍潛入射傷。兩天過後，馬利照常帶傷登台歌唱。旁人問他何以如此？馬利說：「想危害世界的惡徒一天都不願停歇，我怎麼可以休息呢。」