1. To make a selection from a larger group or range. Our parents said we could pick from box of discounted toys. There wasn't much left to pick from by the time we got there.

2. To select a person or thing from a larger group or range. In this usage, a noun or pronoun is used between "pick" and "from." You can pick one puppy from the litter to take home. We're having a hard time picking someone from the pool of applicants.

3. To identify someone or something from a similar group of people or things. Typically used in negative constructions. In this usage, a noun or pronoun is used between "pick" and "from." They wore nondescript clothing and haircuts so you couldn't pick them from a crowd. The inexpensive computer runs so well that you couldn't pick it from a selection of high-end PCs.