Split infinitives occur when additional words are included between to and the verb in an infinitive. Many readers find a single adverb splitting the infinitive to be acceptable, but this practice should be avoided in formal writing.
When he was 11 years old, Itachi was also under orders from his father to enroll in the Anbu half a year later. Itachi was praised highly by Fugaku, who spent most of his time grooming Itachi to inherit the title of leader of the Uchiha, and hence inadvertently neglected his younger son.
As the descendant of the Uchiha, Sasuke is able to use the Sharingan, a bloodline technique exclusive to members of the Uchiha clan. He is first seen using it in a battle against Haku and Zabuza, however, it is revealed in Part II that he first awakened it the night Itachi massacred the Uchiha clan.