评论
打印
1.set off 引发
The powder immediately ignited and set off a chain reaction of explosions.
炸药立即点燃并引发了连环爆炸反应。
2.join hands 携手
Boys and girls, please join hands and bow your heads.
孩子们，请携起手，低下头来。
3.sing in unison 齐声歌唱
ow let's sing the national anthem in unison with the piano accompaniment.
现在我们在钢琴伴奏下齐唱国歌。
