1、to have(many) irons in the fire: to have a lot of activities going on at the same time（同时有许多事，想马上全部做完，但又不知从何开始，似乎忙得不可开交） (来源：英语麦当劳 http://www.EnglishCN.com)
Don't bother him because he has many irons in the fire.
Some people even like to have many irons in the fire.
2、to talk over (one's) head(s): to use large or big words so that audience will not understand exact meaning（指所谈论的内容过于专业或高深，非一般人可以理解；也指有人为了表現自己才学非凡，故意谈些高深理论或用些难字，吓唬別人）
Dr. Lee's lecture was so specialized that he almost talked over our heads.
In order to show his profound knowledge he talks over my head.
3、to put (something) back into (in) its cage: to put something under control (可以控制某件事情，多半指政治、健康等)
We are trying to put inflation back into its cage and our economy is on the mend.
iplomats and politicians need to put aggression and hostility back into its cage.
4、to keep (one's) fingers crossed: to hope something good will happen（祝福某人好运或一切顺利。把食指与中指交叉，祈求好运，是老外的迷信，但在写信或正式场合，多半是用“I wish you best (good) luck!”或“Good (best) luck to you!”）
He keeps his fingers crossed hoping his father will send him more money.
Many people have been keeping their fingers crossed that we can live in a peaceful world.
5、to stretch (one's) legs: to relax or to take a short break（久坐后，把腿舒展一下，或稍微休息一下）
Let's take ten minutes to stretch our legs.
May I take a break so that I can stretch my legs?
During the a long flight from the US to Taiwan, I normally stretch my legs every two hours.
6、to read between the lines：to interpret the hidden meaning or a hidden message; to discern the true fact（从字里行间体会隐含的意义；领会言外之意或能了解其中的真正意义）
As you look at this poem, be sure to read between the lines.
After he re-read the love letter between the lines, he realized that he was dumped by his sweetheart.
7、to let off steam：to give vent to one's anger （发泄、出气，像放掉蒸汽以减少压力似的。这与“to fly off the handle”意思相近，但比“to lose temper”委婉客气些 ）
What will you do if your wife lets off steam?
但是谈到第三者，就可不必太委婉，可用 lose temper:
What will you do if one of your staff lose temper?
Occasionally we should be given a chance to let off steam.
8、to pay through the nose: to pay too much for something or excessively expensive （花费太多，代价过高，与“ to cost an arm and a leg”意义相近）
Don't pay through the nose when you buy the furniture.
Some women paid through the noses for their jewelry.
9、to take center stage：to be in the spotlight（引人注目的中心人物；以某人为公众瞩目的对象）
Mrs. Lin always takes center stage at a party.
President Bush takes center stage wherever he goes.
His constant taking center stage could deprive him of his privacy.
10、to drag(one's)feet: to procrastinate or postpone（慢慢的拖延，行动迟缓，拖拖拉拉）
It is not a good idea to drag your feet when the work needs to be done.
No employers like for their employees to drag their feet on any project.
11、to paint(someone or oneself)into a corner:to trap oneself or someone; to be in trouble（使自己或某人陷入困境, 应该注意的是即使主语是复数形式，corner 仍然用单数）
Don't try to paint yourself into a corner. (不要让自己身陷困境，无法脱身。)
After a heated debate with his boss, Mr. Chen has painted himself into a corner. (和老板激烈的争辩之后，陈先生处境十分不妙。)