instrumental

a.起作用的，有助于，乐器的

instigate, instigation, instigator, instil (US instill), instill, instillation, instinct, instinctive, instinctively, institute, institution, institutionalize, instruct, instruction, instructional, instructions, instructive, instructively, instructor, instrument, instrumentalist, instrumentality, instrumentation, insubordinate, insubordination, insubstantial, insufferable, insufferably, insufficiency, insufficient, insufficiently, insular, insularity, insulate, insulated, insulating, insulating tape, insulation, insulator, insulin,