hot air

基本解釋

It uses hot air.
它使用熱空氣。
“They aren’t selling engines, they are selling hot air out the back of an engine,” says an investment analyst.
一位投資分析家說，“它們不是在售賣引擎，它們賣的是引擎后面排出的熱空氣?！?/li>
But unlike their comrades in that bloody urban battle, the marines now in Afghanistan have, for the most part, thrust their swords into hot air.
但與那場慘烈巷戰(zhàn)的戰(zhàn)友不同，阿富汗的陸戰(zhàn)隊這一次，絕大部分時候，把炎熱的空氣當成了他們的打擊目標。

State-owned media quote the president as saying he is dissatisfied with this month's global-warming summit in Copenhagen, calling it "a lot of hot air."
I'm hot, compared to the air of the room, or cold if I'm somewhere that's warm.
我相對于室內(nèi)的空氣是熱的，或是冷的如果我呆在一個溫暖的地方。
麻省理工公開課 - 熱力學與動力學課程節(jié)選
But if you touch the valve going into your tire which basically measures the temperature of the air going into your tire, that is getting hot, right.
以至于渾身發(fā)熱,如果你摸氣筒的閥門,相當于近似測量了進入輪胎的氣體的溫度，它會很熱，對吧。
麻省理工公開課 - 熱力學與動力學課程節(jié)選

But in 2009, some of the big ones rose like a hot air balloon.
FORBES: Do Rising BRIC Interest Rates Mean Big EM Bond Gains?

If something that someone says is hot air, it is not sincere and will have no practical results.

熱風
The technology of dehydrating wild rice stem using microwave energy in combination with hot air diying was investigated preliminarily.
利用微波能結合熱風干燥對茭白脫水的工藝進行了初步研究。
物理學
熱空氣