求指点：syntax error near unexpected token “fi”的解决办法~~~

[「已注销」]

ch="1"
while [ $ch != "0" ]
do
echo "********************"
echo "0.Exit"
echo "1.Mount USB"
echo "2.Umount USB"
echo "********************"
echo "Please choose number 1,2 or 0:"
read ch
echo " "
if [ $ch = "1" ]
Then
echo "Please insert your USB"
echo "Are you ready?(y/n)"
read ready
if [ $ready = "y" ]
Then
mount /dev/sdb1 /mnt/usb
echo "Your usb are mounted"
fi
elif [ $ch = "2" ]
Then
umount /mnt/usb
echo "Please take your usb"
elif [ $ch = "0" ]
Then
echo "Exit now!"
else
echo "Wrong choice!"
echo "Please choose again!"
fi
echo " "
done

这个脚本运行的时候，会提示第21行（也就是第一次出现fi的地方）有错误啊，如题。求解救！！！在线等~~~

[qq120848369]

小写then啊，大哥。

[如此美丽的你]

[Quote=引用 1 楼 的回复:]

小写then啊，大哥。
[/Quote]
换头像了！

[「已注销」]

[Quote=引用 1 楼 的回复:]
小写then啊，大哥。
[/Quote]


谢谢大哥指点啊！呵呵。。。因为之前是用的小写，提示了错误，改成大写就没问题了，所以就没认为是then的问题了，呵呵。。。现在想想应该是条件判断部分的空格问题所致。
刚学，不懂的东西很多，O(∩_∩)O谢谢~~~