伺机报复: find some way to retaliate; seek one's revenge on [upon] ..
伺机反扑: wait for a chance to spring a counterattack; bide one's time for a counterattack; seek opportunities to launch a counterattack; wait for an opportunity to counterattack
伺机而动: watch for the proper moment for action; keep secretly ready for the right time; see which way the cat jumps; wait for an opportune moment to act; wait for an opportunity to take action; wa