This is the largest clock in the world,- the minute hand is

the subject of first half sentence 'This is the largest clock in the world’ is 'clock',while the subject of the other half is 'the minute hand',it is a part of the clock。Therefore,in the sentence it should be 'of which'Let's change above sentence into 2 seperate ones as:This is the largest clock in the world。The minute hand of the clock is 6 meteres long。You'll see 'of which'='of the clock'。 再问： Thanks for you reply。 Why "where=on/in the clock" can't be used here? In attributive clause, "where" denotes a place, an activity and a range。 I know the minute hand is part of the clock。 To some degree, it is a best answer。