small grammar correction at the start of tutorial 1

Author: simongravelle

lammps-tutorials.tex

@@ -435,19 +435,18 @@ \subsection{Tutorial 1: Lennard-Jones fluid}
 cubic box with periodic boundary conditions (Fig.\,\ref{fig:LJ}).  In
 this tutorial, the temperature of the system is maintained using a
 Langevin thermostat~\cite{schneider1978molecular}, and basic quantities,
-including the potential and kinetic energies, are calculated from the
-simulation.
+including potential and kinetic energies, are calculated from the simulation.
 
 \subsubsection{My first input}
 
-To run a simulation using LAMMPS, you need to write an input script with
+To run a simulation using LAMMPS, you need to write an input script containing
 a series of commands for LAMMPS to execute.  For clarity, the
 input scripts for this tutorial will be divided into five categories,
-which will be filled out step by step.  To set up this tutorial, select
+Which will be filled out step by step.  To set up this tutorial, select
 \guicmd{Start LAMMPS Tutorial 1} from the \guicmd{Tutorials} menu of LAMMPS--GUI, and
-follow the instructions.  This will select and, if needed, create a folder,
+follow the instructions.  This will select (or create, if needed) a folder,
 place the initial input file \flecmd{initial.lmp} in it, and
-open that file in the LAMMPS--GUI editor.  The editor should display the
+open the file in the LAMMPS--GUI editor.  The editor should display the
 following content:
 \begin{lstlisting}
 # PART A - ENERGY MINIMIZATION
@@ -463,13 +462,13 @@ \subsubsection{My first input}
 These five categories are not required in every input script and do not
 necessarily need to be in that exact order.  For instance, the \lmpcmd{Settings}
 and the \lmpcmd{Visualization} categories could be inverted, or
-the \lmpcmd{Visualization} category could be omitted.  Note, however, that
+the \lmpcmd{Visualization} category could be omitted.  However, note that
 LAMMPS reads input files from top to bottom and processes each command
 \emph{immediately}.  Therefore, the \lmpcmd{Initialization} and
 \lmpcmd{System definition} categories must appear at the top of the
 input, and the \lmpcmd{Run} category must appear at the bottom.  Also, the
-specifics of some commands can change after global settings are changed, so the
-order of commands in the input script matters.
+specifics of some commands can change after global settings are modified, so the
+order of commands in the input script is important.
 
 \paragraph{Initialization}