"把放在摇篮内" can be translated into English as "place (it/the baby) in the crib" or "put (it/the baby) in the crib".
Here, "crib" is the common term for a baby's bed, often with slatted sides and used for infants. The choice between "place" and "put" depends on the context and the desired tone, with both being acceptable in this context. If referring specifically to a baby, you can include "the baby" in the sentence for clarity, e.g., "Place the baby in the crib."