a leap in the dark

a daring step or enterprise whose consequences are unpredictable

冒险行动，未知数很大之举

by (或 in) leaps and bounds

with startlingly rapid progress

突飞猛进地

productivity improved in leaps and bounds.

生产率突飞猛进地提高。

leap to the eye

(especially of writing) be immediately apparent

（尤指文字）突现，显眼

by leaps and bounds

Very quickly

非常快地

growing by leaps and bounds.

长得飞快

leap in the dark

An act whose consequences cannot be predicted.

无法预测后果的行为

leap of faith

The act or an instance of believing or trusting in something intangible or incapable of being proved.

信仰不可捉摸：信仰或相信不可捉摸或无法证明之事物的行为或例子