there is a fly in/on [place]
fly 是可数名词，指苍蝇等双翅目昆虫，复数形式是 flies。
There's a fly in my soup.
我的汤里有只苍蝇。
（裤子的）门襟；前裆开口；帐篷门帘；帐篷前帘；（棒球的）高飞球；腾空球；（钓鱼用的）拟饵；飞钓饵；飞行
A true fly (order Diptera), especially the housefly; any two-winged insect.
双翅目昆虫；具有两翅(除少数无翅种类外),亦称真蝇。
Any insect of the order Diptera; characterized by having two wings (except for some wingless species), also called true flies.
飞行行为。
An act of flying.
双翅昆虫,善于飞行
two-winged insects characterized by active flight
尤指蝇科昆虫,如家蝇(其他双翅目包括蚊、蠓等)。
Especially, any of the insects of the family Muscidae, such as the common housefly (other families of Diptera include mosquitoes and midges).
高飞球
A fly ball.
帐篷门帘,可拉开进出的帆布片
flap consisting of a piece of canvas that can be drawn back to provide entrance to a tent
类似但不近缘的昆虫,如蜻蜓、蝴蝶或瘿蝇。
Those or any similar but not closely related insect, such as a dragonfly, butterfly, or gallfly.
覆盖帐篷前部开口的帆布
A piece of canvas that covers the opening at the front of a tent.
服装上的开口,用拉链或暗扣闭合
an opening in a garment that is closed by a zipper or by buttons concealed under a fold of cloth
轻型拟饵,形似昆虫。
A lightweight fishing lure resembling an insect.
裤子、内裤等前面的布条(有时隐藏拉链或纽扣)
A strip of material (sometimes hiding zippers or buttons) at the front of a pair of trousers, pants, underpants, bootees, etc.
胸部锻炼:从两侧伸直手臂移至胸前(亦作flye)。
A chest exercise performed by moving extended arms from the sides to in front of the chest. (also flye)
可伸缩梯子的活动部分
The moving portion of an extendable ladder.
蝶泳(复数通常为flys)。
The butterfly stroke (plural is normally flys).
旗帜的自由边缘
The free edge of a flag.
20世纪60年代流行的一种简单舞蹈,双手在空中挥舞。
A simple dance in which the hands are shaken in the air, popular in the 1960s.
旗帜的水平长度
The horizontal length of a flag.
蝶式期权(四种选择组合)。
A butterfly (combination of four options).
一种锻炼,涉及手臂在肩膀垂直方向的宽幅开合
An exercise that involves wide opening and closing of the arms perpendicular to the shoulders.
风向标指示风吹来方向的部分
The part of a weather vane pointing the direction from which the wind blows.
指南针上标记方向的部分；罗盘卡
That part of a compass on which the points are marked; the compass card.
安装在旋转轴上的两个或多个叶片,用作风扇或通过空气阻力来平衡或阻碍机械运动,如钟表的打击部分
Two or more vanes set on a revolving axis, to act as a fanner, or to equalize or impede the motion of machinery by the resistance of the air, as in the striking part of a clock.
针织机中铰接在针上的部件,用于在针穿透另一个环时保持已接合的环的位置；针舌
In a knitting machine, the piece hinged to the needle, which holds the engaged loop in position while the needle is penetrating another loop; a latch.
纺车或纺纱机中围绕纱锭旋转以扭转纱线的一对臂
The pair of arms revolving around the bobbin, in a spinning wheel or spinning frame, to twist the yarn.
通过击打或猛推穿过梭口的梭子
A shuttle driven through the shed by a blow or jerk.
剧院舞台上的上层屏幕之一
One of the upper screens of a stage in a theatre.
废棉
Waste cotton.
A fly landed on the table.
一只苍蝇落在了桌子上。
用法提示：名词，指双翅昆虫。
He unzipped the tent fly and stepped outside.
他拉开帐篷门帘，走了出去。
用法提示：名词，指帐篷的门帘。
She noticed the fly of his trousers was undone.
她注意到他裤子的开口没拉上。
用法提示：名词，指服装上的开口。
fly 是可数名词，指苍蝇等双翅目昆虫，复数形式是 flies。
There's a fly in my soup.
我的汤里有只苍蝇。
此处的 fly 指裤子前襟的拉链开口，与昆虫无关；常用于提醒别人。
Your fly is open.
你的裤子拉链开了。
棒球中 fly 是高飞球，也可说 fly ball。
He hit a fly to left field.
他打出一个左外野高飞球。
健身中 fly 指双臂从两侧向胸前合拢的夹胸动作，常用复数 flies。
I do three sets of flies at the gym.
我在健身房做三组飞鸟夹胸。
housefly 特指家蝇，是 fly 最常见的通俗含义；仅在明确指普通家蝇时可替换 fly，不能泛指所有双翅目昆虫。
gnat 指体型小、常会叮人的飞虫，只是 fly 的一种；不能用于所有双翅目昆虫，且使用范围较窄。
grammar · medium
易错句子I saw fly on the wall.
正确表达I saw a fly on the wall.
英语中单数可数名词前必须有冠词（如 a/the），汉语没有冠词，因此学习者常漏掉。fly 是可数名词，这里加 a 表示“一只”，句子才完整正确。
grammar · medium
易错句子There are many fly in the kitchen.
正确表达There are many flies in the kitchen.
fly 是可数名词，其复数形式是 flies（辅音字母 + y 变 ies）。汉语名词不标记复数，所以学习者容易保留单数形式。用 flies 才能与 many 搭配，表示多只苍蝇。
仅用于棒球术语义项“高飞球”（fly ball）；指贴地滚动的球，与“fly”相对。不适用于苍蝇、门襟等其他名词义项。
fly（苍蝇/飞虫）有翅膀，是双翅目昆虫；flea 无翅、善于跳跃的吸血小虫，拼写和读音不同（fly /flaɪ/，flea /fliː/）。
作名词表示“飞行”时，fly 较口语、指一次飞行动作；flight 是标准用词，指飞行旅程或航班，可与“直飞、班机”等搭配。
拍苍蝇
He tried to swat a fly that was buzzing around his head.
他试图拍打一只在他头上嗡嗡飞的苍蝇。
高飞球
The batter hit a fly ball to deep center field.
击球手打出一个飞向中外野深处的高飞球。
帐篷门帘
The tent fly flapped loudly in the wind.
帐篷门帘在风中哗啦作响。
裤子拉链没拉
He walked around all morning with his fly open.
他整个上午都裤子拉链没拉，四处走动。
飞蝇钓
They went fly fishing on the river last weekend.
他们上周末去河里飞蝇钓鱼。
飞鸟夹胸
He does chest flies with dumbbells to build his pectoral muscles.
他用哑铃做飞鸟夹胸来锻炼胸肌。
苍蝇属于昆虫纲，这个词是它所属的更大类别。
苍蝇最显著的特征之一就是拥有一对翅膀。
苍蝇飞行时通常发出的声响。
蚊子和苍蝇同属双翅目，都是常见的飞虫。
蝴蝶常被误认为苍蝇一类，但两者亲缘关系较远。
美中不足；煞风景的事
The hotel was wonderful, but the slow wifi was a fly in the ointment.
酒店很棒，但网速慢是美中不足。
暗中观察者；墙上的苍蝇
I'd love to be a fly on the wall when they hear the news.
我多想悄悄看看他们听到这个消息时的反应。
纷纷倒下；大批死亡
The workers were dropping like flies in the heat.
工人们热得纷纷倒下。
嘘，苍蝇，别来烦我，我可是有主的人了。
When a fly buzzed around my picnic, I softly sang, 'Shoo fly, don't bother me.'
当一只苍蝇在我野餐时嗡嗡乱飞，我轻声唱道：“嘘，苍蝇，别来烦我。”
蝇王
In Lord of the Flies, the flies swarm around the pig's head on a stick.
在《蝇王》中，苍蝇聚集在棍子上的猪头周围。
Dictionary facts from ECDICT, WIKTIONARY.