際に/際/際は => occasion, time N2
[際「さい」]して/に([際「さい」]し)/に[際「さい」]しての => At the time of A (which starts now).. N2
Time, Situation
に際して => on the occasion of; at the time of ~ N2
など~ない => Not...at all N3
Description
どのくらい => how long N5
どうもない => No problem N3
Confirm
いちど .... ば/... たら => Just... once N4
Conditions (sufficient conditions)
ほど~ない => is not as… as ~ N3
にどと~ない => No...second time N2
Emphasize negative meaning
…どうりがない => No reason... N2
Emphasize negative meaning
ほど… はない => is not as… as N3
The highest (comparative) level
どの => which N5