Some abstract nouns can be used in a particular sense with a/an, but in the singular only

Some abstract nouns can be used in a particular sense with a/an, but in the singular only:

  • a help: My children are a great help to me. A good map would be a help.

  • a relief: It was a relief to sit down.

  • a knowledge + of: He had a good knowledge of mathematics.

  • a dislike/dread/hatred/horror/love + of is also possible:

  • a love of music a hatred of violence

  • a mercy/pity/shame/wonder can be used with that-clauses introduced by it:

  • It's a pity you weren't here. It's a shame he wasn't paid.

  • a fear/fears, a hope/hopes, a suspicion/suspicions

    These can be used with that-clauses introduced by there:

    There is a fear/There are fears that he has been murdered.