+\fB1h\fR, \fB2h\fR, \fB4h\fR, \fB8h\fR, \fB24h\fR, \fB48h\fR, \fBweek\fR, \fB2weeks\fR, \fBmonth\fR, \fBtrimester\fR, \fBsemester\fR, and \fByear\fR
+select mails received during the last
+1, 2, 4, 8, 24, 48, 7 * 24 hours, 14 * 24 hours, 31 * 24 hours, 92 *
+24 hours, 185 * 24 hours, and 365 * 24 hours respectively.
+.TP
+\fBtoday\fR
+selects mails received since midnight.
+.TP
+\fByesterday\fR
+selects mails received yesterday.
+.TP
+\fBmonday\fR, \fBtuesday\fR, ..., \fBsunday\fR
+select mails received the most recent such day of the week.