2d. Needles in right joints (7) r - n - l - s
18a. Teaching period to break out in test. (8)
t - t - r - a -
21d. Gaze, glance. (4) - o - -
24a. Percentage of possible sales. (6, 5)
- a - - - t - h - r -
if the answer to 21d. is 'look' then this makes the fourth letter of 24a. 'k'
All help appreciated.