7
1.7 singular countable nouns use with and without a / an in scienti fi c English 1. Some singular countable nouns can be used with or without an article with no difference. There
are no clear rules for this, and usage seems to vary from discipline to discipline, and from author to author.
2. If the noun is followed by
of (i.e. to add further details,
then this noun is preceded by a / an.
3. Some singular countable nouns are used without an article when they are used in an extremely generic way.
4. When preceded by
by , means of transport are used without
a / an ; certain time expressions do not require
a / an when used with prepositions.
WITH A / AN WITHOUT A / AN 1
It is stored in a compact form It is stored in
compact form .
1 As these parameters are fixed,
a grammar is determined, what we call
a core grammar” We call this kind of abstraction
“
aggregation.” 1 These were obtained by using
3-chloro-1-propanol
as the Share with your friends: 
