A sentence group is a grammatical unit consisting of two or more sentences that center around one meaning. Sentence groups have three basic features. First, a sentence group contains two or more sentences, each having its own mood and intonation and each ending with a full stop, a question mark, or an exclamation mark in writing. Second, the sentences within sentence groups are related to each other in meaning; the whole sentence group focuses on one meaning. Third, the central meaning expressed by a sentence group can be summed up from the composite sentences in some cases; in others, it is directly expressed by one sentence in the group. For example,
(1) ① sì-gè xiàndàihuà, guānjiàn shì kēxué jìshù xiàndàihuà. four-CLS modernisation, key COP science technology modernisation. ② méiyǒu xiàndài kēxué jìshù, jiù bù kěnéng jiànshè have not modern science technology, then NEG possible construct xiàndài nóngyè, xiàndài gōngyè, xiàndài guófáng. modern agriculture, modern industry, modern defence. ③ méiyǒu kēxué jìshù-de gāosù fāzhǎn, yě jiù have not science technology-SP high speed development, also then bù kěnéng yǒu guómínjīngjì-de gāosù fāzhǎn. NEG possible have national economy-SP high speed development ‘The key to the four modernisations is the modernisation of science
and technology. 1 Without the modernisation of science and technology, it is impossible to construct modern agriculture, industry, or national defence. Without the speedy development of science and technology, there will be no speedy development of the national economy’.