Managers at global firms consistently rank cross-cultural understanding as an essential 　　1　　 of any 21 st century employee's basket of skills. At the most basic level, that includes interpersonal functions, such as meeting clients, dealing with sensitive conversation topics, and avoiding cultural faux pas. At a deeper level, it involves understanding behaviors, perspectives, and subtle spoken and written nuances.

To master basic skills, managers say training courses, videos, and reading materials can accomplish the task. 　　2　　 , to go further than that, it may be necessary to travel or live abroad and acquire fluency in the target language. And while all these measures are helpful, there is, of course, no 　　3　　 for experience.

1. (A) education　(B) forefront　(C) knowledge　(D) component

2. (A) Therefore　(B) However　(C) Consequently　(D) Particularly

3. (A) substitutes　(B) substituted　(C) substitute　(D) substitutable

解析：

1. 答案 (D)
依據空格前的 essential ( 不可或缺的 ) 以及空格後的 basket of skills ( 技能組合 ) 可判斷， cross-cultural understanding( 對於跨文化的了解 ) 應該是員工們必須具備之能力的一重要部分，因此選 (D) component ( 要件 ) 。

2. 答案 (B)
根據文意，空格前的句子 To master basic skills … can accomplish the task. ( 想要精通基本的技巧 ... 可以達成這項任務。 ) 與空格後的 … to go further than that, it may be necessary to travel or live abroad… (... 若想要更上一層樓，那麼就可能需要到海外旅遊或生活 ... 。 ) 呈現相反對照的關係。因此，答案應選具有此功能的連接副詞 (B) However ( 然而 ) 。

3. 答案 (C)
of course 為插入的片語，其前的 there is 為「有」之意，引導「存在句」 (existential sentence) ，而句子的主詞應為其後的「名詞」。故本題選 (C) substitute ( 替代品 ) 。注意，選項 (A) 若視為名詞，則是複數形，但前面使用的動詞為單數的 is ，故不可選。