Answers:
有三种样式的占位符:
!variable
,指示应按原样插入文本。这对于将变量插入电子邮件等内容很有用。
$message = t("If you don't want to receive such e-mails, you can change your settings at !url.", array('!url' => l(t('My account'), "user/$account->uid")));
@variable
,它指示文本应通过check_plain运行,以转义HTML字符。将其用于Drupal页中显示的任何输出。
$title = t("@name's blog", array('@name' => $account->name));
%variable
,指示该字符串应转义为HTML并使用theme_placeholder()突出显示,默认情况下会突出显示该主题。
$message = t('%name-from sent %name-to an e-mail.', array('%name-from' => $user->name, '%name-to' => $account->name));