Question: beats are in a quaver?
Answer: A semibreve lasts for four crotchet beats. A minim lasts for two crotchet beats. A quaver lasts for half a crotchet beat - so there are two to the time of a crotchet. A semiquaver lasts for a quarter of a crotchet beat - so there are four to the time of a crotchet.