Slice apart leaves and stems. Cut stems across in ½-inch slices on a slant. Cut leaves in ½-inch slices. Slice carrots very thin on a slant.
Heat a wok and pour oil around the rim. Add bok choy stems and carrot slices and toss over moderately high heat until almost tender—4-5 minutes. Add leaves, sugar, and soy sauce; toss until most of liquid evaporates and th