Bhutan is one of the most isolated nations in the world, 30 foreign influences and tourism regulated by the government to preserve its traditional Tibetan Buddhist culture.
答案：(B) with
【句型】with + 受詞 + 過去分詞，with foreign influences and tourism regulated 表示「外國影響力與觀光業受到政府管制」這個伴隨狀況。by／for／in 都無法構成這種「with + 受詞 + 分詞」的獨立結構。
with 這個字，你的印象大概只有「和……一起」與「用……」，看到它後面接著一長串 foreign influences and tourism regulated by the government，會覺得沒有一個介系詞放得進去。
答對率不到五成，鑑別度只有 28，是本批最低的一題。這一題難，卻連高分群考生也常失手，原因在於這個句型擺在句子最後面、後面又跟著一長串修飾語，形狀不容易認出來。先把空格後面拆成兩層：foreign influences and tourism 是受詞，regulated by the government 是補充說明這個受詞處於什麼狀態，還原成完整子句就是 foreign influences and tourism are regulated by the government（外國影響力與觀光業受到政府管制）。能還原成「受詞是或處於那個狀態」，就確定是 with ＋ 受詞 ＋ 受詞補語（表附帶狀態）這個課本長教的句型，空格填 with。同一年第 11 題也考 with，但那一題考的是 be satisfied with 這個固定的字詞搭配，兩題擺在一起，正好看出同一個介系詞的兩種考法。
by、for、in 後面都只能接名詞或名詞組，接不了「受詞加補語」這兩層；把它們填進去，regulated by the government 那一串就沒有地方可以掛。
with ＋ 受詞 ＋ 受詞補語（表附帶狀態）、with his eyes closed（閉著眼睛）、with the engine running（引擎還發動著）、be regulated by（受……管制）、preserve a culture（保存文化）、isolated（孤立的、與外界隔絕的）。
The Kingdom of Bhutan is a landlocked nation situated between India and China. The entire country is mountainous, 26 a small strip of subtropical plains in the extreme south. The elevation gain from the subtropical plains to the glacier-covered Himalayan heights exceeds 7,000 m.
Its traditional 27 is based on forestry, animal husbandry and subsistence agriculture. However, these 28 less than 50 of the GDP now that Bhutan has become an exporter of hydroelectricity. Besides, cash crops and tourism are also 29.
Bhutan is one of the most isolated nations in the world, 30 foreign influences and tourism regulated by the government to preserve its traditional Tibetan Buddhist culture. It is often described as the last surviving refuge of traditional Himalayan Buddhist culture.