Learn French: Nous laissons les valises passer dans le scanner pour le contrôle. - We let the suitcases pass through the scanner for the check.

The verb laisser (to let or to allow) is followed by the object (les valises) and then an infinitive verb (passer). This matches the English structure exactly: we let [the suitcases] [pass].

Could I put the verb passer before les valises instead?

Yes, you can! With laisser plus an infinitive, noun objects can usually go between the two verbs or after the infinitive. Both Nous laissons les valises passer and Nous laissons passer les valises are completely natural and mean the same thing. Just remember that if you used a pronoun instead of a noun, it would have to go before the first verb: Nous les laissons passer.

Why use dans instead of a word for "through" when talking about the scanner?

While English says pass through the scanner, French simply says pass in the scanner (passer dans le scanner). You will often see dans used where English uses through when talking about going inside a machine, a tunnel, or a defined physical space.

Does le contrôle mean the control here?