continue
1 abide, carry on, endure, last, live on, persist, remain, rest, stay, stay on, survive
2 go on, keep at, keep on, keep one's hand in, keep the ball rolling, keep up, maintain, persevere, persist in, prolong, pursue, stick at, stick to, sustain
3 draw out, extend, lengthen, project, prolong, reach
4 carry on, pick up where one left off, proceed, recommence, resume, return to, take up
1 abdicate, leave, quit, resign, retire, step down
2 & 4 break off, call it a day, cease, discontinue, give up, leave off, pack in (Brit. informal) quit, stop