When the weather is bad, individuals tend to focus more on their work rather than thinking about activities they could 29 outside of work.
答案：(C) engage in
【句型】engage in 固定片語「從事」，表示「思考下班後可能從事的活動」；break off（中斷）、approve of（贊成）、take over（接管）都不合。
engage 你先想到的多半是「訂婚」（be engaged to someone）或電話占線、廁所有人的 engaged，所以看到 engage in 就不敢選。engage in 是「從事、參與」，其實就是你國中學過的 take part in（參加）和 participate in（參與）的同一組，只是語氣正式一些。把新詞掛在舊詞上就好記多了：take part in a contest（參加比賽）、participate in the discussion（參與討論）、engage in outdoor activities（從事戶外活動）。
先看空格前後。activities they could {29} outside of work，這是一個省略了關係代名詞的關係子句，還原成完整寫法是 activities that they could engage in outside of work（他們下班後可以從事的活動）。再把它拆成兩句更清楚：They could engage in the activities outside of work.＋These are the activities.注意 in 留在句尾，這正是關係代名詞被省略之後常見的樣子，看到動詞後面「少一個介系詞」時要有警覺。
break off（中斷、突然停止）用在關係或談話，像 break off the negotiations（中斷談判）。approve of（贊成、認可）後面接的是你認可的做法或人。take over（接管、接手）後面接的是職務或公司。三個代進去都無法搭配 activities。
engage in（從事、參與）、be engaged in（忙於、投入於）、take part in（參加）、participate in（參與）、break off（中斷、突然停止）、approve of（贊成、認可）、take over（接管、接手）、focus on（專注於）。
Research has proven that weather plays a part in our moods: Warmer temperatures and exposure to sunshine increase positive thinking, whereas cold, rainy days bring anxiety and fatigue. 26 , many people believe that bad weather can reduce productivity and efficiency.
There is, however, a significant 27 between such beliefs and the actual effect of weather on people's performance at work. Using empirical data from laboratory experiments 28 observations of a mid-sized Japanese bank in real life, researchers find that weather conditions indeed influence a worker's focus. When the weather is bad, individuals tend to focus more on their work rather than thinking about activities they could 29 outside of work. But photos showing outdoor activities, such as sailing on a sunny day or walking in the woods, can greatly distract workers and thus 30 their productivity.
The findings conclude that workers are actually most productive when the weather is lousy—and only if nothing reminds them of good weather.