trace element

substance occurring or needed only in extremely small amounts (esp in the soil, for the proper growth of plants) 微量元素, 痕量元素（尤指土壤中的, 植物正常生长所需要的）.

town crier, town hall, town house, town planning, town-folk, townee, townsfolk, `townspeople, township, townsman, toxaemia (also toxemia), toxic, toxicity, toxicologist, toxicology, toxin, toy, toy animal, Toyota, toyshop, trace, traceable, tracer, tracery, trachea, tracheotomy, trachoma, tracing, tracing-paper, track, track and field, track down, track events, track out, track record, track suit, tracked, tracking station, tract, tractability, tractable,