踩 ㄘㄞ ˇ cǎi 线 ㄒㄧㄢ ˋ xiàn 踩 ㄘㄞ ˇ cǎi 線 ㄒㄧㄢ ˋ xiàn to scout for a tour operator to reconnoiter a potential tour itinerary (tennis) to commit a foot fault