Once you have tasted the outdoor life in southern California, it's hard to return to Montana in winter.

一旦你体验过南加州的户外生活，再要回到蒙大拿过冬就会感到很难。

《柯林斯英汉双解大词典》

Sometimes it's hard to tell another person how you feel, especially if you don't know how they feel about you in return.

有时去告诉他人你对他的感觉是挺难的，特别是你并不知道他对你的感觉时。

youdao

It's hard to tell at this point which return value means what.

现在要弄清返回值的具体含义还比较困难。

youdao

Adding inactivity to injury, this is especially true in locations where many people exercise accompanied to music, airplanes (hey, it's hard to return those seats to their upright positions), the New York City subway system, and the streets of cities other than Mountain View, CA. Indeed, most WiFi-friendly environments are also laptop-friendly and thus support access to not only Yahoo Music and its competitors, but high-quality free internet radio from last.fm, Slacker, and others.

ENGADGET: Switched On: Music in the air (Part 2)

"It's hard to find a return these days that isn't correlated to the stock market, " says Jones.

FORBES: Magazine Article

It sounds nice, but it's hard to prove a return on investment.

FORBES: If This Corporation Could Paint ...