千钧一发的英文：
[Literal Meaning]
thousand/ancient measure of weight equal to 30 jin (about 15kg)/one/hair
to hang the weight of 15 tons by a single hair

[解释]
形容情况万分危急。

[Explanation]
imminent peril

[例子]
在这千钧一发的时刻，他没有考虑自己，跳到水中去救那个六岁的男孩。

[Example]
At the imminent moment, he did't care about himself and dived into the river to save that six-year-old boy.

[英文等价词]
a narrow scrape
by a hair
close call
depend on a thread
hang by a hair
hang by a thread
touch and go
toucher
within a hair of

To hang by a hair thread
千钧一发

A thousand catty hang upon one hair;an extremely delicate and dangerous situation
千钧一发

Have a narrow escape; have a close escape
千钧一发;幸免

The firemen arrived at the critical moment.
消防队员在千钧一发之际赶到。

Nobody seemed interested in the wantonly imperiled life
好象对那个千钧一发的生命谁都没有兴趣。

It was a narrow escape when I avoided my teacher.
"我侥幸地避开了我的老师,真是千钧一发。"

I sprang for the foot-path and saved myself by the fraction of a second
我急忙跳到人行便道上，在千钧一发间幸免于难。

The hero saves the day by shooting the kidnappers and rescuing the hostages just in the nick of time.
就在千钧一发之际，那位英雄开枪射向劫匪，解救了人质，使局面转危为安。

"It was I," said a sailor of a frank and manly appearance "and it was time, for you were sinking."
“那是我呀，”一个外貌诚实直爽的水手说道，“真是千钧一发，因为你正在往下沉呢。”

It was time, for just as I jumped the deck burst with a noise like the broadside of a man-of-war
真是千钧一发哪！我刚跳离，甲板就嘣的一声象一艘主力舰上边众炮齐发似的炸裂了。