Complex sentence: Lawrence Livermore National Laboratory (LLNL) is one of three laboratories in the United States where classified work towards the design of nuclear weapons is undertaken, the others are Los Alamos National Laboratory and Sandia National Laboratories.
Split into simpler sentences: Lawrence Livermore National Laboratory (LLNL) is one of three laboratories in the United States where classified work towards the design of nuclear weapons is undertaken. The others are Los Alamos National Laboratory and Sandia National Laboratories.