例句：

　　He kept his finger on the trigger.

　　他的手指一直勾著扳機(jī)。

　　Don't pull the trigger!

　　別扣扳機(jī)！

　　Stress may act as a trigger for these illnesses.

　　壓力可能會(huì)成為引發(fā)這些疾病的原因。