Visitors to the National Museum can avoid long lines at the ticket booths by purchasing tickets .
A. in advance
B. in detail
C. out of order
D. with caution
网友回答
(答案→)A. in advance
B. in detail
C. out of order
D. with caution
解析：考查介词短语：A. in advance提前B. in detail详细的C. out of order秩序混乱的，D. with caution小心谨慎的，句意：到国家博物馆的游客可以通过提前预订票避免在售票厅排长队。选A。