A sentence is a unit of language consisting of more than one word that is grammatically linked. A sentence must contain a main clause, which is typically made up of a subject and a verb, and it may also contain an object or a complement. A main clause may also be linked to another clause by a conjunction.

Sentences can be classified according to their structure. There are broadly four types of sentence in English:

1. Simple sentences - a sentence made up of a single main clause.
   • Individual responsibility for education is emphasised over education as a public good.
   • As a result, the international student experience has been criticised as undemocratic and lacking transparency.
2. Compound sentences - a sentence made up of two main clauses and connected with a coordinating conjunction.
   • Philosophy is important and it has a causal efficacy on policy and practice. (two main clauses connected with the coordinating conjunction and)
   • International students encounter new freedoms and opportunities but they also come across new constraints.
3. Complex sentences - a sentence made up of a main clause and a subordinate clause, connected with a subordinating conjunction.
   • A neoliberal philosophy has resulted in a global education system, which is characterised by high student fees and the presence of for-profit providers. (one main clause connected to a subordinate clause, in this case a relative clause, with the subordinating conjunction which)
   • Archer (2003) argues that both structure and agency are interdependent. (a that clause)
4. Complex-compound sentences - a combination of a compound and one or more complex sentences.
   • The international student experience represents a significant change in social structure as participants travel long distances and international students may be distanced from existing networks. (a main clause linked to a subordinate clause with the subordinating conjunction as, connected to a main clause with the coordinating conjunction and)

Coordinating Conjunctions

A coordinating conjunction links together two main clauses:

• for
• and
• nor
• but
• or
• yet
• so

Subordinating Conjunctions

A subordinating conjunction links a main clause to a subordinate clause:

•  whlle
• as
• although
• whereas
• if
• as soon as
• before
• in order to

Some prepositions can be used as subordinating conjunctions (followed by an -ing clause or a noun).

• You can apply for university by completing a UCAS form online. (by + -ing)
• Solar sensors will measure the light intensity around the Sun due to scattering by aerosols in the atmosphere. (due to + -ing)
• Despite the Luftwaffe's around-the-clock bombing of Malta, the Axis supply convoys to North Africa had been cut to pieces. (despite + -ing)