black and white=something which is extremely clear 像黑与白一样“黑白分明的，明确地”
He told her in black and white that she couldn’t leave the house while he was out.
他明明白白地告诉她，他不在时，她不得离开这座房子。
dos and don’ts=the rules 哪些能做（dos）哪些不能做（don’ts），指“规则，规定”。
There are various do’s and don’ts about driving in the UK.
在英国开车有很多规定。
haves and have nots = people who are rich and those who are not 穷人和富人
In London you can find the haves and have nots of the population.
在伦敦有穷人也有富人。
ins and outs = the details 细节问题
I don’t know the ins and outs of the situation, so I can’t really advise you.
我不了解具体情况，所以不能给你建议。
odds and ends = small pieces of various items 剩余物，零星物品。odd, end都有“剩余的”意思。
She made a stew with the odds and ends she found in the fridge.
她炖了炖在冰箱里找到的剩余食物。
rights and wrongs = all the good points and bad points of a situation 优缺点
Regardless of the rights and wrongs of company policy, you need to give a month’s notice.
且不论公司政策的好坏，你至少要提前一周给出通知。
ups and downs 沉浮，兴衰
ups and downs = very good times and very bad times 沉浮，兴衰
They have a lot of ups and downs in their relationship.
他们的关系几经波折。
come and go = use somewhere as your base 来来去去
Feel free to come and go as you please!
你可以来去自如。
back and forth = not to stay still, but to keep travelling between two places 来回地，往复地
I’m so glad I’m moving. I was getting sick of going back and forth every day. Now my journey to work will be a lot quicker.
真高兴我要搬家了，我已经受够了每天要来回上班。现在去上班要近多了。
cat and mouse = doing something in the same way that a cat plays with a mouse
The guerillas played a cat and mouse game with the much better-equipped army.
游击队和装备精良的军队玩起了猫捉老鼠，搞得他们晕头转向。
trial and error = to do something new by making experiments and occasionally failing 反复试验，不断摸索
The new computer system has been installed. But it’s a bit trial and error at the moment – nobody really knows how to use it.
新的计算机系统装上了，但还在不断摸索中，没有人真正懂怎么使用。
flesh and blood = your family 一家人，如同血与肉
I have to help him if I can – he’s my flesh and blood.
如果能我会帮助他，他是我的家人。