step in

插入，介入

steering, steering committee, steering lock, steering-column, steering-wheel, steersman, stein, stellar, stem, Sten, stench, stencil, steno, stenographer, stenography, stentorian, step, step by step, step down, step forward, step out, step up, step-, step-father, step-ladder, step-parent, stepbrother, `stepsister, stepchild, stepfather, stepfather, `stepmother, stepparent, steppe, stepping-stone, stepson, `stepdaughter, stereo, stereo-, stereophonic, stereoscope, stereoscopic, stereotype,