"Child labor" is, generally speaking, work for children that harms them or exploits them in some way (physically, mentally, morally, or by blocking access to education).
How to make an apple pie
How to make an apple pie. Step 1. Apple. Step 2. Use a child to cut it. Step 3. Bake Pie. Step 4. Child Labor
( z1 thing :manner-of ( z2 make :ARG1 ( z3 pie :mod ( z4 apple ) ) ) )