Complex sentence: Bedwell tells Mrs Holland's badly-treated servant girl, Adelaide, that she must find a Sally Lockhart, so, under pretense of being on an errand, Adelaide goes to the firm of Lockhart & Selby and asks for Sally.
Split into simpler sentences: Bedwell tells Mrs Holland's badly-treated servant girl, Adelaide, that she must find a Sally Lockhart. Under pretense of being on an errand, Adelaide goes to the firm of Lockhart & Selby and asks for Sally.