In the dark
choshek (kho-shek')
the dark; hence (literally) darkness; figuratively, misery, destruction, death, ignorance, sorrow, wickedness -- dark(-ness), night, obscurity.
they dig through
chathar (khaw-thar')
to force a passage, as by burglary; figuratively, with oars -- dig (through), row.
houses
bayith (bah'-yith)
a house (in the greatest variation of applications, especially family, etc.)
which they had marked
chatham (khaw-tham')
to close up; especially to seal -- make an end, mark, seal (up), stop.
for themselves in the daytime
yowmam (yo-mawm')
daily -- daily, (by, in the) day(-time).
they know
yada` (yaw-dah')
to know (properly, to ascertain by seeing); used in a great variety of senses, figuratively, literally, euphemistically and inferentially
not the light
'owr (ore)
illumination or (concrete) luminary (in every sense, including lightning, happiness, etc.) -- bright, clear, + day, light (-ning), morning, sun.