Conjunctions are joining words. And is a conjunction that provides the link between two words (for example, "The teachers and the students arrive by bus each day"). Other conjunctions (as, although, than) are required to link two things in the same sentence (for example, "Although learning to write effectively can take some time, it is worth the trouble in the end"; or "As should be apparent, the issues here are straightforward"; or "Psychology is more interesting than Mathematics"). The conjunctions that often present problems for writers are however, nevertheless, and moreover). They must be used to link ideas in adjacent sentences. The following sample sentences show correct and incorrect usage of these conjunctions.

• Learning to write effectively can take some time, however, it is worth the effort, and you might have to work hard, nevertheless, you should try.
  Learning to write effectively can take some time. It is, however, worth the effort. You might have to work hard. Nevertheless, you should try.