名詞 clearance:

1. the distance by which one thing clears another; the space between them
2. vertical space available to allow easy passage under something
   同義詞：headroom, headway
3. permission to proceed

1. Let me tell you some details about clearance.
   讓我告訴你一些通關的細節(jié)。

clear.ance

n.（名詞）
The act or process of clearing.
清潔，清掃：清潔的行為或過程
A space cleared; a clearing.
清理過的空間；清光林木的空曠地
Abbr. cl.
縮寫 cl.
The amount of space or distance by which a moving object clears something.
清除區(qū)域：移動物體其清除某物的空間或距離的大小
The height or width of a passage:
凈空，余隙：通道的高度或?qū)挾龋?/br>例句：
an underpass with a 3-foot clearance.
有3英尺凈空的高架橋下通道

An intervening space or distance allowing free play, as between machine parts.
空隙，間隙：允許自由運動所介入的空間或距離，如在機器零件之間的
Permission for an aircraft, ship, or other vehicle to proceed, as after an inspection of equipment or cargo or during certain traffic conditions.
結(jié)關，準許通行：讓飛機、輪船或其它交通運輸工具繼續(xù)前進的許可，如經(jīng)過對設備和貨物的檢查或在特定的交通狀況下
Official certification of blamelessness, trustworthiness, or suitability.
證明書：無過失、可靠或稱職的官方證明
A sale, generally at reduced prices, to dispose of old merchandise.
清倉大拍賣：處理舊貨的銷售，通常減低價格
Abbr. cl.The passage of checks and other bills of exchange through a clearing-house.
縮寫 cl.票據(jù)交換：通過票據(jù)交換所的支票傳遞或其它帳單的交換
Physiology
【生理學】
The removal by the kidneys of a substance from blood plasma.
清除：腎將血漿中一種物質(zhì)的移出
Renal clearance.
腎清除