對等連接詞顧名思義所引導的結構前後要平行對稱。
1. 單字對等連接詞：and, or, but, yet, nor等，其前後要平行對稱。
例：1. The people in my town are friendly, cheerful and hardworking. (平行形容詞)
2. Did she leave by bus or by train? (平行介系詞片語)
3. He worked hard, but he failed. (平行子句)
註：nor(也不)，so(也是)只能引導子句平行，且後面的子句要倒裝。
例：1. Mary wants to go, so do I.
2. He can speak English very well, so can I.
3. He is not a soldier, nor am I.
4. He didn’t go to the party, nor did I.
上列倒裝要特別注意到(a)前後動詞時態要一致，(b)前面若用be動詞，則後面亦用be動詞，前面若用助動詞則後面亦用同樣助動詞，前面若為一般動詞則後面用do, does, did來倒裝。
2. 複合對等連接詞：both A and B(兩者皆是)，neither A nor B(非A也非B)，either A or B(A或B其中之一)，not only A but also B(不傴是A同時也是B)，not A but B (不是A而是B)，A but not B(A而不是B)，A as well as B(A跟B)。
注意要點：
(a) 上列連接詞所引導的A與B要平行對稱。
(b) 上列結構當主詞時，動詞的一致性亦非常要。
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Both A and B+複數動詞
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Neither A nor B+ V (單複數與靠近動詞的元素一致)
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Either A or B
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A as well as B+ V (與A一致)
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Not A but B+ V (強調B，故與B一致)
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A but not B+ V (強調A，故與A一致)
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Not only A but also B (強調B，故與B一致)
