91. Duration of time and a date or point in time may be expressed
not only by use of the prepositions "dum", during, and "je", at, on,
but also (as in English) without the use of any preposition. When no
preposition is used, the word or words indicating time are put in the
accusative case:
Li restis tie la tutan semajnon (dum la tuta semajno),
he stayed there the whole week (during the whole week).
Sxi estis felicxa longan tempon (dum longa tempo),
she was happy a long time (during a long time; for a long time).
Ni rajdos tagon kaj nokton (dum tago kaj nokto),
we shall ride a day and a night (during a day and a night;
for a day and a night).
Mi venis dimancxon (je dimancxo), I came Sunday (on Sunday).
Tiun horon (je tiu horo), li forkuris,
that hour (at that hour) he escaped.
92. Although generally preferable, an accusative construction must
be carefully placed, or avoided altogether, if confusion with other
accusatives (expressing direction of motion, direct object, etc.) might
result:
Mi volas iri Bostonon je lundo, I wish to go to Boston on Monday.
Mi volas iri al Bostono lundon, I wish to go to Boston Monday.
Lundon mi volas iri Bostonon, Monday I wish to go to Boston.