x's and o's 成语
two's company (three's a crowd)
better to leave two people together than for a third person to interfere My friend wanted to come along on the date between me and my girlfriend but I told him that two's company and three's a crowd so he stayed home.
two's company, three's a crowd
two people are happier than three, the third person is not welcome "Jill asked, ""Can I invite Ginger?"" Jack replied, ""Two's company, three's a crowd."""
who's own
used to inquire the owner of an item. Example: someone would hold up a pencil and, speaking to a group, ask "Who's own?"
who's who
1.a reference book containing short biographical entries on the outstanding persons in a country,industry,profession,etc.名人录;名人词典
Do you have a copy of“Who's Who in Japan”?你有《日本名人录》吗?
2.who this one is and who that one is;who the different ones in a group of people are谁是谁
It took the new teacher a few days to remember who was who in the class.老师花了几天时间才记住班上学生的名字。
Do's and don't's
The do's and don't's are what is acceptable or allowed or not within an area or issue, etc.
two's company; three's a crowd|company|crowd|three
An informal way to express a situation when two people desire privacy and a third one is present.

A proverb.
Beth and Carl wanted to be alone so when Maggie joined them they said, "Two's company; three's a crowd."
who's who|who|who is who
informal 1. Who this one is and who that one is; who the different ones in a group of people are or what their names or positions are.
It is hard to tell who is who in the parade because everyone in the band looks alike. It took the new teacher a few days to remember who was who in the class. Compare: WHICH IS WHICH. 2. Who the important people are.
John didn't recognize the champion on television. He doesn't know who is who in boxing. After about a year, Mr. Thompson had lived in this town long enough to know who was who. Compare: WHAT'S WHAT.
do's and don'ts
do's and don'ts Rules or customs concerning some activity, as in
It's important to know the do's and don'ts of diplomatic receptions. This expression alludes to what one should and should not do or say. [c. 1900]
look who's talking
look who's talking You're in no position to criticize, as in
I wish Kate would be on time for once.—You do? Look who's talking! This colloquial idiom dates from the mid-1900s, although another version,
you can't talk, is a century or so older.
two's company
two's company see
three's a crowd.
x's and o's
1. sports The symbols acclimated to denote the players on one's aggregation (and usually those of the opposing team) in a diagram of a comedy (i.e., the accumulation the players will booty back aggravating to account or move the ball). The appellation generally refers to the plays themselves. That drillmaster is abundant with the x's and o's, but the team's beheading has been actual disappointing.2. By extension, ability of how article works. Before you alpha on that report, alarm Shelly—she knows all the x's and o's of the budget.Learn more: and