もしかすると/もしかしたら~かもしれない => perhaps; maybe; perchance; by any chance ~ N3
しか~ない => only; nothing but N4
だけしか~ない => only N3
いつしか => before one knows N2
Accept, agree
しかし => But, nevertheless N5
Change the subject of the story
たしかに/なるほど~かもしれない => might; perhaps N3
Speculation
ないかしら => I wonder (feminine) N4
Aspiration
しかない => have no choice but ~ N3
いかにも…らしい => indeed; really; truly N3
Accept, agree
てもよろしいでしょうか => May I... N4
Allow
~いはしまいか => whether or not; considering options N1
Base, base
…くらいの…しか…ない => Only… at low level N2
Limit, limit