滥竽充数 to fill a gap with inferior things
Explanation
滥竽充数比喻没有真才实学的人，混在行家队伍里充数，或以次充好，冒充有本领。
This idiom refers to someone who is not really talented, who mixes with experts to increase the number, or pretends that inferior goods are of high quality and pretends to be capable.
Origin Story
战国时期，齐宣王特别喜欢听吹竽，每次都要三百人一起吹。有个叫南郭先生的人，他根本不会吹竽，却想混在乐队里享受俸禄。他来到齐宣王面前，装模作样地吹了起来。齐宣王听不懂竽乐，加上人多嘈杂，根本听不出南郭先生是否吹得好坏，于是就让他混在乐队里，一起领俸禄。后来宣王死了，他的儿子湣王即位，他喜欢听人单独吹竽，喜欢分辨吹竽的好坏。南郭先生一听，心里害怕，知道自己骗不了湣王了，于是连夜逃跑了。
During the Warring States period, King Xuan of Qi particularly loved to listen to the ensemble of yue, each time with three hundred people playing together. There was a man named Nan Guo, who couldn't play the yue at all but wanted to mix with the band and enjoy the salary. He came before King Xuan, pretending to play. King Xuan did not understand yue music, and with so many people playing, it was impossible to tell if Mr. Nan Guo played well or badly, so he let him join the band and receive his salary. Later, King Xuan died, and his son, King Min, ascended the throne. He liked to listen to people play the yue solo and could distinguish between good and bad yue music. As soon as Mr. Nan Guo heard this, he was afraid, knowing that he could no longer deceive King Min, and he fled overnight.
Usage
用以比喻那些没有真才实学的人，混在行家里充数，或者以次充好，冒充有本领。
It is used to describe those who do not have real talent or ability, mixing with experts to make up the numbers or pretending to have superior skills by passing off inferior goods as high-quality ones.
Examples
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他虽然不会做饭，却在厨房里滥竽充数，结果把菜都做坏了。
ta suiran bu hui zuofan, que zai chufang li lan yu chong shu, jieguo ba cai dou zuo huai le.
Although he can't cook, he pretended to know in the kitchen, and ended up ruining the dishes.
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这个小组里有些人滥竽充数，工作效率很低。
zhe ge xiaozu li you xie ren lan yu chong shu, gongzuo xiaolv hen di.
Some people in this group are just pretending to be capable and the work efficiency is very low.
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会议上，有些人只是滥竽充数，并没有真正参与讨论。
huiyi shang, you xie ren zhishi lan yu chong shu, bing meiyou zhenzheng canyu taolun.
In the meeting, some people just pretended to participate without really contributing to the discussion.
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他滥竽充数了好几年，最终还是被公司辞退了。
ta lan yu chong shu le hao ji nian, zhongyu haishi bei gongsi cituile.
He pretended to be capable for several years, but eventually, he was fired by the company.
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不要滥竽充数，要踏踏实实地做好每一件事。
buya lan yu chong shu, yao tata shi shi di zuo hao mei yi jian shi.
Don't just pretend; work steadily and do a good job in every aspect.