用法:
1 without compulsion; willingly 自愿地; 自动地; 主动地.

用法:
2 without payment; free of charge 志愿地; 无偿地; 义务地.

• trace element
• tracer
• tracery
• trachea
• tracheotomy
• trachoma
• tracing
• tracing-paper
• track 1
• track and field
• tracked
• track events
• tracking station
• track record
• track suit
• tract 1
• tractability
• tractable
• traction
• traction-engine
• tractor
• tractor-trailer
• trad
• trade 1
• trade gap