单选题   ______ the project in time, the staff were working at weekends.
 
【正确答案】 D
【答案解析】[考点] 考查非谓语动词。 由后句“the staffwere working at weekends.”可知周末一直工作的目的就是为了按时完成计划，不定式作目的状语，故选D。