Colossus Cryptic 227 (UK Edition)

Hello

Could anyone help me out there ? I am still struggling with a few clues:

34a) Duty rotates at ten

?a?

66a) Burns becomes Roebuck's business associate

s?a?s

74a) Trait evident in biased jugdges and brunettes

?n?a???e?s

70d) Company has nothing for Bill's partner

c?o

Many thanks

SHBABE