Bellum scrīptūrus sum quod populus Rōmānus cum Iugurthā … gessit .
war.ACC write-PTCP-PROSP-M.NOM.SG I.am which.N.ACC.SG people.NOM Roman.M.NOM.SG with Jugurtha.ABL  wage-PERF.3SG
I propose to write (lit. ‘I am going to write’) of the war which the Roman people waged with […] Jugurtha.