Cevap :

They may be in the museum now.
They might be in the museum now.
They could be in the museum now.  Şimdi müzede olabilirler. (Belki şimdi müzededirler.)

They may be watching television at the moment.
They might be watching television at the moment.
They could be watching television at the moment. Şu anda televizyon seyrediyor olabilirler.

They may spend the weekend here.
They might spend the weekend here.
They could spend the weekend here. Hafta sonunu burada geçirebilirler. (Belki de hafta sonunu burada geçirecekler.)