# Include a standalone .tex file (which contains two languages) partially (one language or the other)

I am going to collect questions from faculty members written in two languages and combine them in a single main.tex exam file.

I have created a sample main.tex file as follows:

\documentclass{article}
\usepackage{standalone}

\newif\ifen \newif\iftr
\newcommand{\en}[1]{\ifen#1\fi}
\newcommand{\tr}[1]{\iftr#1\fi}
\entrue

\begin{document}

\en{Mathematics 101 midterm}
\tr{Matematik 101 vize}

\begin{enumerate}
\item (questions/question1.tex)
\item (questions/question2.tex)
\end{enumerate}

\end{document}


I would like to have a single .tex file for every question, and they should be able to compile on their owns.

Also, it would be great if both languages are presented when a question is compiled (so, when professors are preparing the questions they can check for translation errors).

So, what format should the question1.tex file have, in order to display both languages when its compiled, but hide one language when the main.tex is compiled?

I tried something like this but it didn't work:

\documentclass{article}

\newif\ifen \newif\iftr
\newcommand{\en}[1]{\ifen#1\fi}
\newcommand{\tr}[1]{\iftr#1\fi}
\entrue \trtrue

\begin{document}
\en{What is the answer to 7+5?
\begin{itemize} \item 10 \item 11 \item 12 \end{itemize}
}

\tr{7+5 sonucu nedir?
\begin{itemize} \item 10 \item 11 \item 12 \end{itemize}
}
\end{document}