#!/usr/bin/env python
x ="there are %d people in the world" %10
bi="binary"
donot="don't"
y= "Those who kown %s and Those who %s %s " % (bi,donot,bi)

print x 
print y

print  "I said :%r ." % x
print "I also said %r ."%y

hilarously =False
joke_evaluation ="do you think this  joke is  funny ?! %r "

print  joke_evaluation % hilarously

w = "this is  left  ...."
e =  " right string"
print  w+e