Complex sentence: In his 1956 short story "The Next Tenants", Arthur C. Clarke describes tiny machines that operate at the micrometre scale--although not strictly nanoscale (billionth of a meter), they are the first fictional example of the concepts now associated with nanotechnology.
Split into simpler sentences: In his 1956 short story "The Next Tenants", Arthur C. Clarke describes tiny machines that operate on a microscale (millionth of a meter). While these machines are not nanoscale (billionth of a meter), they are the first fictional example of the concepts now associated with nanotechnology.