abstain
/əbˈsteɪn; əb`sten/ v[I, Ipr]
~ (from sth)
1 keep oneself from doing or enjoying sth, esp from taking alcoholic drinks; refrain 戒（尤指酒）; 戒除.
2 decline to use one's vote 弃权（不投票）
At the last election he abstained (from voting/the vote). 上次选举时他弃权了（没投票）.