Never was night so still；never was a sky so deeply blue,nor stars so bright and serene.譯文：夜從未如此沉寂，天從未如此深藍，星亦從未如此明亮。英語句子盡管繁簡交替，長短交錯，但結構完整，形式仍不致流散。原因何在？其主要原因是英語有許多聚集句子的手段（形態標誌、連接詞、it、there等）使句子結構完整，等等。O.Jespersen（1951年）指出，“It became an invariable custom to have a subject before the verb,and therefore a sentence which did not contain a subject was felt to be incomplete；many of the rules concerning the use of it are seen to be due on the one hand to the speaker’s wish to conform to certain patterns of sentence construction found in innumerable sentences with other subjects or objects,and on the other hand to his wish to avoid clumsy combinations which might even sometimes lead to misunderstandings.”英語句子複雜而不流散的另一重要原因是：句子成分或詞語之間必須在人稱、數、性和意義等方麵保持協調一致的關係（concord or agreement）。這一原則包括以下三個方麵。
a）語法一致原則（grammatical concord）：即在語法形式上保持主語與謂語動詞之間數與人稱的一致（如動詞單數第三人稱加-s/-es），主語和表語之間數的一致（如She is a student-They are students），賓語和賓語補足語之間數的一致（如I found the boy a bright pupil-I found the boys bright pupils），人稱代詞、某些限定詞和它們的照應對象之間的人稱、數和性的一致（如The girl has seen her mother），等等。
b）意義一致原則（notional concord）：即在意義上保持一致，如主語形式為複數，但意義為單數，謂語動詞依據意義采取單數形式，反之亦然。如：My family are all fond of playing table tennis.Two thousand dollars is more than he can afford.非限定動詞作狀語或定語，其邏輯主語或邏輯賓語必須與句子主語或被修飾語保持協調一致，如：
Sent to zoos in Tokyo and other cities,the pandas are reported to have settled down very well.這些熊貓送到東京和其他城市的動物園以後，據說都適應的很好。
c）就近原則（principle of proximity）：即謂語動詞的人稱和數往往和其最靠近的詞語保持一致。
如：例1.Either you or I am going.譯文：要麼你去，要麼我去。
例2.Either you,nor I,nor anyone else knows the answer.譯文：你和我，以及其他任何人，都不知道這個答案。英語句子成分之間這種協調一致的原則，使句子結構受到形態的約束，因而句式嚴謹、規範、刻板，缺乏彈性。相比之下，漢語的主謂結構要複雜得多。主語可有可無，可中途變換或隱藏主語，主語可以是名詞、動詞或形容詞，可表施事、受事，也可表時間、地點。
例3.他有個女兒，在北京工作，已經打電話去了，聽說明天就能回來。
He has a daughter,who works in Beijing.Someone has phoned her and it is said that she will be back tomorrow.
例4.鳳姐還欲問時，隻聽二門上傳出雲板，連叩四下，將鳳姐驚醒。
Before Xifeng could ask more she was woken with a start by four blows on the chimebar at the second gate.漢語的謂語也複雜多樣：可以是名詞、動詞或形容詞，可以是多個動詞或多個詞組，還可以沒有動詞。
例1.天高雲淡。
The sky is high and the clouds are pale.
例2.他出國留學去了。
He has gone abroad for further studies.
例3.我介紹他加入協會。
I recommended him for membership of the association.