You've got to keep to the speed limit
你必须遵守限速规定。
You should always keep to the speed limit.
什么时候你都不得超过最高速度限制。
Keep to the nearside lane.
不要偏离左边的车道。
Let's keep to the subject, or you'll get me too confused.
别跑题，否则你会把我搞糊涂的.。
He had been unable to keep to his schedule.
他没能遵循自己的计划。