at: at duskza soumraku
dawn: from dawn to duskod rána do večera
whichever: to dusk or 10.00pm, whichever is soonerdo soumraku nebo do 22.00, podle toho, co nastane dřív
soumrak: za soumrakuat dusk
šeřit se: Šeří se.The dusk is falling., It's getting dark.