Unit 21: repaint, redo, refill, rebuild, discolor, untidy, dislike, uneven, rewind, unlucky, reread, unsure, reheat, unpack, unpaid, distrust, recount, displease, unload, disorder, remake, unclear, rewrite, unfair, unkind, redecorate, unfamiliar, unusual, rearrange, discontinue
Unit 22: picture, person, perfect, attend, number, support, common, welcome, offer, expert, harvest, survive, suppose, perform, escape, helmet, allow, fellow, barber, tender, lesson, until, yellow, hello, garden, filter, candid, disturb, narrate, rascal
Unit 23: current, danger, canyon, plastic, bottom, hollow, member, borrow, organ, compose, lumber, seldom, engine, pillow, carpet, garbage, master, arrow, army, thirty, sudden, follow, enjoy, happen, forget, challenge, vessel, submerge, eddy, venture
Unit 24: electric, question, jacket, sink, ache, blanket, mistake, squirrel, track, stomach, change, bridge, twice, strange, carriage, damage, edge, glance, since, lodge, unlucky, uneven, rebuild, dislike, repaint, recount, unload, disorder, unsure, displease, expert, common, picture, welcome, perfect, barber, allow, escape, perform, survive, canyon, organ, compose, danger, borrow, army, carpet, garbage, seldom, arrow, unfamiliar, redecorate, challenge, average, narrate, excellence, barracuda, speckled, submerged, disturb