let down

基本解释

The plane let down gently before landing at the airport.
飛機在機場著陸以前徐徐下降。
She wanted to have her skirt let down several centimetres.
她想把裙子放長幾厘米。
http://dict.hjenglish.com
If Rapunzel simply let down her hair and the prince started climbing immediately, her hair would not break, but it might rip out.
如果長發公主剛將她的頭發放下王子就立刻攀爬的話，她的頭發就不會斷，但是，它很有可能會被拔掉。

"We have now to concretize the measure which have been agreed upon 11 April and we have to send a clear signal that we will not let down Greece, and I think that is the bottom line of everything."
So I'm going to comment those out, and let's go down to this piece of code, and uncomment it.
那麽我會把這些注釋上，讓我們看看這段代碼，取消注釋。
麻省理工公開課 - 計算機科學及編程導論課程節選
So let me write that down, it's how much memory do I need to complete a computation.
讓我把它寫下來,儅我計算的時候。
麻省理工公開課 - 計算機科學及編程導論課程節選

Some newspaper and magazine companies, feeling let down by the Kindle electronic reader from Amazon.com Inc.
FORBES: Where the Kindle's real muscle lies

If you let someone down, you disappoint them, by not doing something that you have said you will do or that they expected you to do.
let down
If something lets you down, it is the reason you are not as successful as you could have been.