明亮的灯光会引发她的偏头痛。

Bright lights ___trigger her migraines.

警官提醒新手不要随意触碰手枪的扳机。

The officer reminded the rookie not to touch the ___trigger of the pistol carelessly.

他的评论引发了激烈的讨论。

His comment ___triggered a heated discussion.