In general passive with -s describes an abstract proces - time and place unregarded - whereas passive with blive describes an event in time and place: "happen that...". The modal verbs all have more than one meaning and tend to have one meaning in combination with -s passive and another in combination with blive passive. The exercises forcus on some of the more common meanings, but do not cover all.

Skal....-s is an instruction, a rule or a planned process: Jeg skal klippes på mandag. (I'll have my hair cut next monday.)

Skal blive expresses a promise or an assurence: Han skal nok blive klippet pænt hos Navy-Hairdo! (Navy-Hairdo will cut his hair neatly, I assure you!)

Choose the right combination in the drop-down list

Bare rolig frue: Pakken skal blive leveretleveres på hans fødselsdag!

Varerne skal blive leveretleveres torsdag, det står på sedlen der.