Add punctuation: On 15 July 1997 the Commission adopted a White Paper on the sectors and activities excluded from the Directive on working time COM97 334 final not published in the Official Journal in which it presented the characteristics of each sector and the various possible approaches
A: On 15 July 1997 the Commission adopted a White Paper on the sectors and activities excluded from the Directive on working time [COM(97) 334 final - not published in the Official Journal], in which it presented the characteristics of each sector and the various possible approaches.

Add punctuation: The narrowing from rheumatic fever occurs from the fusion melting together of the edges commissures of the valve leaflets
A: The narrowing from rheumatic fever occurs from the fusion (melting together) of the edges (commissures) of the valve leaflets.

Add punctuation: Books III IV and V treat spherical trigonometry which of course is of major importance in astronomy
A:
Books III, IV and V treat spherical trigonometry which, of course, is of major importance in astronomy.