Is $L = a^{n}b^{n+m}c^{m} | n,m \geq 0$ a context free or a recursive language?
Here's a hint:


Could you make a grammar for $a^nb^n$, $n\ge 0$?
Could you make a grammar for $b^mc^m$, $m\ge 0$?
Could you make a production that concatenates the languages in (1) and (2) above?