PHP: ternary, print &amp echo

Quick PHP question: why does

(0==0) ? print ‘Zero’ : print ‘Not Zero’;

output a message, but

(0==0) ? echo ‘Zero’ : echo ‘Not Zero’;

generates an error (Parse error: parse error, unexpected T_ECHO in /var/www/print.php on line 2)?

According to the manual, both print and echo are language constructs, not functions. However, [...]