A study examined adult readers' phrasing ability to determine (1) if passage difficulty was a salient variable in readers' sensitivity to phrase boundaries in reading; (2) if phrase sensitivity was an issue of concern for young adult readers; and (3) if difficulties in phrasing were due to an overabundant or an inadequate sensitivity to phrase boundaries in texts. Data were obtained from 60 undergraduate college students, 30 of whom were identified as good readers and 30 of whom were enrolled in a reading skills course, by asking them to identify phrase boundaries in two texts varying in difficulty. Results revealed an interaction between reading ability and text difficulty. In the easier text, both good and poor readers performed at the same level. With the more difficult text, the performance of the poor readers remained at the same level as that of the easier text. Further analysis indicated that errors in phrasing were due more to a relative insensitivity, rather than too great a sensitivity, to phrase boundaries. Continued investigations into the development of readers' phrasing ability appear to be called for. (One figure and five tables of data are included; 27 references are attached.) (KEH)