how to add a virtual directory in apache with support to php files?

["Star Liu" <minxinjianxin@gmail.com>]

I'm learning to use php. when i drop my Welcome.php into /var/www,
which is the default root directory for localhost, and visit it by
http://localhost/Welcome.php, it can display the html normally; but i
want my php files in another place like /root/MyLife/LifeOS/StarLiu/,
so I add a entry into /etc/apache2/sites-available/default, like this:

Alias /php/ "/root/MyLife/LifeOS/"
<Directory "/root/MyLife/LifeOS/">
		Options Indexes FollowSymLinks MultiViews
		AllowOverride None
		Order allow,deny
		allow from all
</Directory>

then i visit it by http://localhost/php/StarLiu/Welcome.php, but it
pops out the download dialog to download the Welcome.php file.

it seems i didn't configure it correctly, how can i fix it? thanks

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