Please stop talking. 請不要講話.
Listen carefully. 注意聽.
Please be quiet. 請安靜.
Please keep quiet. 請保持安靜.
Don't push others. 不要推其他人.
Please pay attention. 請注意.
You are too noisy, please stop. 你太吵了,請停止.
Please don't make noise. 不要吵.
Return to your seat. 回到你的座位上去.