The word "branch" can refer to several related ideas. Literally, it means a part of a tree that grows out from the trunk. Figuratively, it can describe something that splits off from a main part—like a branch of a company (a separate office or store in a different location), a branch of government (such as the executive or judicial branch), or even a branch of knowledge (like biology or history). In all cases, a "branch" suggests something that extends or divides from a central source.

“branch” 這個字很實用，既可以當名詞，也可以當動詞喔！當名詞時，它最常見的意思是「樹枝」，像是 “The bird is sitting on a branch.”；延伸來說，它也可以指「分店」或「分部」，例如 “The bank opened a new branch downtown.”。當動詞時，branch 常和介系詞 out 連用，變成 “branch out”，表示「擴展業務、拓展領域」，句子可以說 “The company plans to branch out into online sales.”；如果只用 branch，也可以指「從主體分岔出去」，像 “The river branches into two smaller streams.”。記得別把動詞和名詞搞混了，用的時候注意搭配的介系詞和上下文，就能說得自然又道地！

The verb "expand" means to grow larger, spread out, or increase in size, number, or detail—for example, "The company plans to expand into new markets." The noun "expansion" refers to the process or result of expanding, such as "The expansion of the company created new job opportunities." While "expand" focuses on the action of growing or enlarging, "expansion" refers to the outcome or ongoing process of that action.

「expand」是動詞，表示「擴大、拓展」的意思，而其名詞形就是「expansion」。比方說，你可以說：The company plans to expand its services overseas.，或者用名詞：The expansion of the metro system has made commuting easier. 這兩個詞最常搭配空間、規模、業務或想法等概念，強調從小到大、由少至多的增長過程；若想談更正式的經濟或科技領域，也常看到 economic expansion 或 memory expansion 這類組合。總之，只要想到「變大、變多」，就可以聯想到這對兄弟字！