&lt;?php$a  =  '12345';echo 'qwe{$a}rty';?&gt;
A. qwe12345rty
B. qwe{$a}rty
C. error
D. no output
Answer:A
&lt;?php$a  =  '12345';echo 'qwe{$a}rty';?&gt;
A. qwe12345rty B. qwe{$a}rty C. error D. no output
Explanation: qwe{$a}rty, single quotes are not parsed.