An observation balloon
氣象觀測氣球
?? 詞語組成解析
an
[?n]
art. 一（在元音字母前代替不定代詞a）;一任一某一;一個;
balloon
[b?'lun]
n. 氣球;熱氣球;[建]球飾;
vt. 膨脹，漲大;乘熱氣球飛行;使激增;
adj. 氣球狀的;（貨物等）分量輕而體積大的;（分期付款）最后一筆大數目的;
vi. 乘氣球飛行;膨脹;激增;
ball球+oon表名詞 → 氣球
??? 情景例句
If you don't apply to the relevant department your passport will never be approved.
如果你不向有關部門申請，你就得不到護照。
This river is one third as long as that river.
這條河只有那條河的三分之一長。
Then he put a piece of cheese in his pocket and went away.
然后把一塊乳酪裝進衣袋里走了。