20.
(A) host
(B) eject
(C) construct
(D) tutor

host主人，東道主；（電視或廣播節目的）主持人；寄主，宿主

eject（用武力）驅逐，逐出，趕出；使（從機器中）彈出

construct建造；構築；構成，組成；構想；觀念；編造，杜撰

tutor家庭教師，私人教師

eject
verb
[ T often passive ]
to force someone to leave a particular place
（用武力）驅逐，逐出，趕出

A number of fans had been ejected from the bar for causing trouble.
一些足球迷因爲鬧事被趕出酒吧。
 
to leave an aircraft in an emergency using an ejection seat
（緊急情況下連坐椅一起從飛機中）彈射出來
to come out of a machine when a button is pressed, or to make something do this
使（從機器中）彈出

How do you eject the tape?
怎樣才能把磁帶彈出來？

The coffee machine suddenly ejected a handful of coins.
咖啡自動售賣機裡突然彈出一把硬幣。