用an，因为ugly的发音以元音音素开头，所以需要使用an来表示。
此规则适用于所有以元音音素开头的单词。
使用a或an来表示一个单词的正确性在英语使用中非常重要，需要注意单词的发音和拼写来选择正确的冠词。
用 an
ugly是元音字母开头的。
Toads have an ugly appearance but they are useful.蟾蜍外表丑陋，但很有用。
The baboon is very ugly.狒狒非常丑陋。
What an ugly mug!多难看的脸！
His face was covered in ugly red blotches.他脸上有许多难看的红色大斑点。
The ugly caterpillar will change into a beautiful butterfly.丑陋的毛虫会变成美丽的蝴蝶。
His house looks terrible with those pieces of ugly furniture.那些难看的家具使得他的家看上去一团糟糕。
