seesaw
noun [ C ] uk/ˈsiː.sɔː/ us/ˈsiː.sɑː/ (US also teeter-totter)
跷跷板
a long board that children play on. The board is balanced on a central point so that when a child sits on each end they can make the board go up and down by pushing off the ground with their feet.
seesaw
verb [ I ] uk/ˈsiː.sɔː/ us/ˈsiː.sɑː/
（情绪、局势等）摇摆不定，不断反复，交替
to change repeatedly from one emotion, situation, etc. to another and then back again
His mind seesawed between hope and despair all through those weeks. 那几个星期里，他一会儿心怀希望，一会儿又感到绝望，心情变来变去。