at the drop of a hat

(informal)without delay or good reason

(非正式)立即；莫名其妙地，一有刺激就

he used to be very bashful, blushing at the drop of a hat.

他曾经非常害羞，会莫名其妙地脸红。

drop one's aitches

omit the ‘h’ sound from the beginning of words (in Britain often regarded as a sign that the speaker belongs to a low social class)

省略单词开头的‘h’音（在英国常被认为是说话者社会阶层低下的标志）

drop asleep

fall gently asleep, especially without intending to

不知不觉睡着

drop the ball

(N. Amer. informal)make a mistake; mishandle things

(北美，非正式)犯错，出错，做错事

I really dropped the ball on this one.

在这件事上我的确出了错。

drop a brick

(Brit. informal)make an indiscreet or embarrassing remark

(英，非正式)失言；出言不慎

he dropped a brick when he admitted that he knew where we were going.

他不小心说漏了嘴，承认他知道我们要去哪儿。

drop a clanger

(Brit. informal)make an embarrassing or foolish mistake

(英，非正式)做事出岔子，犯愚蠢的错误

he admitted he might have dropped his first managerial clanger.

他承认自己可能在管理上出了第一个岔子。

drop a curtsy

(Brit.)make a curtsy

(英)行屈膝礼

drop dead

die suddenly and unexpectedly

突然倒毙，猝死

she had seen her father drop dead of a heart attack.

她曾看见她父亲因心脏病发作而猝死。

drop a (或 the) dime on

(US informal)inform on (someone) to the police

(美，非正式)向警方告发（某人）

drop one's guard

abandon one's habitual defensive or protective stance

丧失警惕，放弃戒备

drop a hint (或 drop hints)

let fall a hint or hints, as if casually or unconsciously

（装作漫不经心地）暗示

he was dropping hints that in future he would be taking a back seat in politics.

他暗示将来要在政坛退居二线。

a drop in the ocean (或 in a bucket)

a very small amount compared with what is needed or expected

沧海一粟

the £550 million saving is likely to be a drop in the ocean.

节约的5.5亿英镑有可能是沧海一粟。

drop someone a line

send someone a note or letter in a casual manner

给…写短信（或便条）

drop me a line at the usual address.

按老地址给我寄封短信。

drop names

drop me a line at the usual address.

按老地址给我寄封短信。