For some people, a single cup of coffee in the morning will make them feel nervous and 30 them up all night.
答案：(A) keep
【句型】keep sb up 固定片語「讓某人熬夜不睡」，表示咖啡因會讓某些人「整晚睡不著」；remain、stand、check都不合這個字詞搭配。
本題大考中心未公布逐題答對率，以下不談數據，只談觀念。
四個選項都是動詞，而 remain 與 stand 都帶著「保持、維持」的味道，讀起來好像也能表達「一直醒著」。這一格要看空格後面有沒有受詞。
先看結構：a single cup of coffee in the morning will make them feel nervous and ___ them up all night.and 連接兩個動作，前面是 make them feel nervous，所以空格也要是原形動詞，而且後面帶著受詞 them 與副詞 up。能走「動詞 ＋ 受詞 ＋ up」並且意思是「讓某人保持某種狀態」的是 keep：keep somebody up 就是「讓某人熬夜、睡不著」，整句是「早上一杯咖啡就會讓他們緊張，還讓他們整晚睡不著」。keep 的這個用法很常見，都是「使某人維持在某個狀態」：keep sb waiting（讓某人一直等）、keep sb company（陪伴某人）、keep sb busy（讓某人忙個不停）、keep sb informed（隨時告知某人）。
remain：是不及物動詞（remain calm、remain silent），後面不能直接接受詞 them，形態就不合。stand：stand sb up 確實是通行的說法，但意思是「放某人鴿子」，與咖啡因讓人睡不著完全無關。check：check sb up 不是通行的說法（要說 check up on sb 調查某人，或 have a checkup 做健康檢查）。
keep sb up（讓某人熬夜、睡不著）、keep sb waiting（讓某人一直等）、keep sb company（陪伴某人）、stand sb up（放某人鴿子）、check up on sb（調查、探視某人）、be perfectly calm（完全冷靜）。
Tea and coffee contain caffeine, a substance that can make you active. 26 you do not feel fully engaged after you wake up in the morning, drinking coffee at breakfast can mean the 27 between a productive day and never arriving at work.
Caffeine is also the main ingredient in many "diet pills." It boosts metabolism, thereby 28 the body to burn more calories. If you take a 29 to a different time zone, caffeine can help you overcome jet lag. Most hotels have coffee and tea service in the room for this very reason.
Every individual handles caffeine differently. For some people, a single cup of coffee in the morning will make them feel nervous and 30 them up all night. Other people can down five cups and be perfectly calm.