<s>
Lexical	B-General_Concept
simplification	I-General_Concept
is	O
a	O
sub-task	O
of	O
text	B-General_Concept
simplification	I-General_Concept
.	O
</s>
<s>
It	O
can	O
be	O
defined	O
as	O
any	O
lexical	B-General_Concept
substitution	I-General_Concept
task	O
that	O
reduces	O
text	O
complexity	O
.	O
</s>
