1. Insist on（upon）
指坚持认为某种想法正确或坚称某种说法属实，尤指与他人的想法或说法相左，也可指坚决要求做某事。
She insisted on her innocence.
她坚称自己无罪。
We insist on the highest standards at all times.
我们始终坚持最高标准。
Our buyers insist on high standards of workmanship and materials.
我们的买主对工艺和材料坚持要高标准。
They insist on playing their music late at night.
已是深夜，他们却依然在放音乐。
They insisted upon being given every detail of the case.
他们坚持要求说明事情的整个来龙去脉。
We'll insist on discussing this issue.
我们将抓住这个问题不放。
He insisted on telling us all the gory details about their divorce.
他坚持要给我们讲他们离婚的种种细节。
If you insist on leaving now, please go ahead.
你一定要走，那就请便吧。
I insist on paying for the damage.
我坚持要赔偿损失。
They insist on sticking to the letter of the law.
他们坚持严守法律的字面意义。
The manager insists on all his employees coming to the picnic.
经理坚持要求所有员工都参加野餐。
They insisted on it that the motor should be repaired as soon as possible.
他们坚持电[发]动机应当尽快修理。
She insisted that he should leave for Shanghai.
她坚持要他去上海。
They insisted that we not eat meat.
他们坚持不让我们吃肉。
2.keep up 指坚持好的习惯，比如：坚持锻炼，坚持学习，坚持早起，坚持看书等坚持一个反反复复的动作或事情，含义有恒心，有毅力，不半途而废的意思。相当于stick to：
Do you still keep up your English?
你仍在坚持学英语吗？
We kept up a correspondence for many years.
我们保持了很多年的通信联系。
She has kept up physical training for several years without interruption.
她坚持锻炼，多年来从未间断。
I was so hungry all the time that I could not keep the diet up for longer than a month...
我无时无刻都觉得饿，节食坚持不到一个月就放弃了。
She was unable to keep up the pretense that she loved him.
她无法继续假装爱他了。
I enjoy our friendship and try to keep it up.（注意代词it在副词up的前面。）
我珍惜我们的友谊，而且努力要把它保持下去。
If you stick to the study of English, you will surely be able to master it.
如果你坚持不懈地学习英语，你一定会掌握它的。
He never sticks to anything for very long.
他做任何事总不能持久。
Business isn't good but we're managing to hold our own.
生意不景气，但我们正设法坚持下去。