なければならない => Must do A; have to A N4
Can, Should, Must
といえば/というと/といったら => N3
Considering, Concerning
ねばならない => Must A N2
Needs, Requirements
てばかりはいられない => Cannot always A N2
Needs, Requirements
てはいけない => May not A, must not A N4
Can, Should, Must
わけにはいかない => Must not A, Must A N3
Needs, Requirement
[決「けっ」]して~ない => Won’t, isn’t N3
Will, Decision, Doing
と[言「い」]わせれば => On the view of N1
Based/focused/depending on
かといえば => Although A is expected, B results N2
Contrast,Surprise
なくてはいけない => Must do A; have to A N4
Can, Should, Must
そういえば => Speaking of .., A by the way, A; N2
Considering, Concerning
たいばかりに => B is done solely because of A N2
Reason, Result, Response