###HUMAN: what is the last d5 1/2ns dose that patient 65962 was prescribed in 05/2103?, ###ASSISTANT: SELECT prescriptions.dose_val_rx FROM prescriptions WHERE prescriptions.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 65962) AND prescriptions.drug = 'd5 1/2ns' AND STRFTIME('%y-%m', prescriptions.startdate) = '2103-05' ORDER BY prescriptions.startdate DESC LIMIT 1