-\fBb <regexp>\fR (body) selects mails whose body matches the
-regexp. Evaluatin such a condition requires to read the original
-mboxes completely, which can be slow. However, header conditions are
-checked first to read the bodies only for mails which fulfill them
-entirely.
+\fB8h\fR, \fB24h\fR, \fB48h\fR, \fBweek\fR, \fBmonth\fR, \fBtrimester\fR,
+and \fByear\fR selects mails received during the last 8, 24, 24, 48, 7
+* 24 hours, 31 * 24 hours, 92 * 24 hours, and 365 * 24 hours respectively.