    Seutence 1! A $- S00. millioa ‘natural-gas-  “fired -power plant -, for, example.-, .couid  replacé ‘up’ to. $100 million’.in boilérs  yearly’ without. adding “new ‘smog. controls    Sentence 2: A- $500 million ‘coal-fired  pover plant-, “for éxample., ‘could replace  $ 100° million ‘in. equipment yearly without  “adding Ten pollution comerots————    