Complex sentence: A new Senate was formed in March 1917 by Oskari Tokoi, but it did not reflect the socialists' large parliamentary majority: it comprised six social democrats and six non-socialists.
Split into simpler sentences: A new Senate was formed in March 1917 by Oskari Tokoi. The cabinet did not reflect the socialists' large parliamentary majority; it comprised six social democrats and six non-socialists.