踩线

to scout for a tour operator / to reconnoiter a potential tour itinerary / (tennis) to commit a foot fault

variant of 踩[cai3]

to step on / to tread / to stamp / to press a pedal / to pedal (a bike) / (online) to downvote

variant of 線|线[xian4]

thread / string / wire / line / CL:條|条[tiao2],股[gu3],根[gen1] / (after a number) tier (unofficial ranking of a Chinese city)

group on a tour to get acquainted with the local situation