问一下一个初中英语问题？急急急！

u不是呀，因为他音标的第一个是j，所以是a，音标的第一个是a e i o u才是an

u的发音[ju:]不是元音音素
20个元音音素例子：(注意：下面空方括号是不知道怎么输入的音标)
1) [i:] sea, he, see, piece, ceiling
2) [i]sit, build, miss, myth
3) [e] bed, desk, head,
4) [ æ] bad, land, bank, stamp
5) [a:] car, fast, class, plant, calm, aunt
6) [ ɔ] hot, want
7) [ ɔ:] door, more, sport, ball, warm, author, court, bought, caught
8) [u:] good, who, blue, soup,
9) [u] look, put, women, could
10) [ ʌ] cup, come, blood, rough
11) [ ə:] girl, work, serve, nurse
12) [ə ] cadre, ago, forget, polite, dollar, doctor, famous, Saturday
13) [ei] cake, they, play, eight, great,
14) [ai] bike, die, neither, light, try, find, height, eye
15) [əu ] phone, cold, boat, soul, grow
16) [au] house, town
17) [ɔi ] boy, oil
18) [iə ] dear, idea, deer, here, fierce,
19) [ɛə ] pear, care, there, f