In a subordinate clause, one clause is always part of another clause. This forms a complex sentence. There are usually three main types of subordinate clauses:
- Noun clause: A clause that serves as a noun in the sentence, usually signaled by the use of wh-words, that, or zero relative.
- Adverbial clause: A clause that serves as an adverb in the sentence, usually signaled by the use of subordinating conjunctions, such as: as, if, when, before, after, because, unless, although, etc.
- Relative clause: A clause that serves as an adjective in the sentence, usually signaled by the use of wh-words, that, or zero relative.
- If a crash comes in Germany, we will have a financial situation something like that at the outbreak of war, and there will be a demand for a moratorium all round.
- What we require is a National Emergency Government.
- Understanding how a planet generates and gets rid of heat is essential if we are to understand how that planet works.
- His Majesty impressed upon them that before they left the Palace, some communiqué must be issued, which would no longer keep the country and the world in suspense.
- The Prime Minister said that he had the resignation of his Cabinet in his pocket, but the King replied that he trusted there was no question of the Prime Minister's resignation.
- That the British eventually accepted the American view in most details shows that they had largely subsumed the aviation issue in the larger question of economic viability.
In academic writing, cleft sentence is also commonly found. A cleft sentence consists of two parts, often starting with "it" or "wh-". It-clefts are relatively frequent in academic texts (Biber, Johansson, Leech, Conrad & Finegan, 1999, p. 959), while Wh-clefts are more common in conversation. The purpose of the cleft is to focus on or draw attention to one part of the clause. It-cleft sentences consist of "it" as the subject of the clause, a form of the verb "BE", the focused item, with a relative clause appearing at the end. For example:
- It was this government which ruled Britain until May 1940, when yet another coalition governed Britain until 1945.
- Both continued to develop; but it was the commemoration of the martyrs that came to swamp the Christian calendar during the fourth century.