Use an ellipsis mark, three spaced periods, to indicate that you have deleted words from an otherwise word-for-word quotation.
Shute acknowledges that treatment for autism can be expensive: “Sensory integration therapy . . . can cost up to $200 an hour” (82).
If you delete a full sentence or more in the middle of a quoted passage, use a period before the three ellipsis dots.
“If we don’t properly train, teach, or treat our growing prison population,” says Luis Rodríguez, “somebody else will. . . . This may well be the safety issue of the new century” (16).
NOTE: Do not use the ellipsis mark at the beginning or at the end of a quotation. Readers will understand that the quoted material is taken from a longer passage. (If you have cut some words from the end of the final quoted sentence, however, MLA requires an ellipsis mark.)